1 Use of Diverse Cattle Breeds to Understand Marbling Development

Use of Diverse Cattle Breeds to Understand Marbling Development and Growth for

the Production of High-Quality Beef

Dissertation

Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy

in the Graduate School of The Ohio State University

Jerad Robert Jaborek, M.S.

Graduate Program in Animal Sciences

The Ohio State University

2019

Dissertation Committee

Alejandro E. Relling, Advisor

Francis L. Fluharty, Co-Advisor

Kichoon Lee

Luis E. Moraes

Henry N. Zerby

Copyrighted by

Jerad Robert Jaborek

2019

Abstract

This research focuses on adding value to feedlot cattle, with additional interest being directed towards increasing the understanding of marbling development and growth in cattle. Marbling score is used to determine beef USDA quality grade because marbling can impact beef eating satisfaction by increasing the three meat sensory characteristics: tenderness, juiciness, flavor. However, marbling development or accumulation can be impacted by a variety of factors including: genetics/breed, animal age at the initiation of feeding/finishing, animal age at harvest, body weight at harvest, diet composition, health, etc. The research presented herein, expands upon the existing information regarding marbling development and growth in cattle. The first study investigates implementing a crossbreeding strategy on Jersey dairy farms, where a terminal beef sire would be mated to a proportion of the herd to increase the value of the male offspring compared with purebred Jersey steers. In general, crossbred Jersey cattle, sired by Angus, SimAngus, and Red Wagyu bulls, had a greater ADG and lesser G:F compared with purebred Jersey steers. As a result of the lesser ADG of purebred Jersey steers, they required the greatest amount of time on feed. Crossbred Jersey cattle achieved greater final body weights with fewer days on feed. Purebred Jersey cattle had a lesser backfat thickness, but deposited a greater percentage of kidney fat compared with crossbred Jersey steers. Crossbred Jersey cattle had a greater marbling score and USDA quality grade compared with purebred Jersey steers. The USDA YG equation did a poor job of predicting carcass cutability of all Jersey influenced cattle in this study. Overall, crossbred Jersey cattle had a greater boxed beef price and boxed beef value compared with purebred Jersey steers. Sire selection criteria for Jersey crossbreeding programs should focus on retail yield and should consider the use of growth enhancing technologies to increase muscle deposition.

The second study was designed to further investigate marbling development in cattle. Wagyu and Angus sired cattle were compared at a similar age and days spent on feed or at a similar body weight endpoint to compare feedlot performance, carcass composition, and the expression of marbling related genes. Two Wagyu sires were used in this study, one selected for growth (LMR Fukutsuru 729T) and the other selected for marbling ability (OW Yasufuku 229Y). When compared at a similar age and days spent on feed, Angus sired cattle had a greater ADG, DMI, and G:F compared with Yasufuku sired cattle, while Fukutsuru sired cattle were similar to Angus sired cattle, except for having a lesser DMI. Therefore, after a similar number of days spent on feed, Angus sired and Fukutsuru sired cattle had a greater off-test weight. Wagyu sired cattle had a greater estimated percentage of KPH, while Yasufuku sired cattle had a greater marbling score and USDA QG compared with Angus sired cattle at a similar age and days spent on feed. When compared at a similar off-test body weight, Angus sired cattle had a greater ADG, DMI, and G:F, spent fewer days on feed, were younger at harvest, and had a lesser total DMI over the course of the entire study. Yasufuku sired cattle had a greater marbling score, USDA QG, and 6th rib fat thickness compared with Angus sired and Fukutsuru sired cattle. At both endpoint comparisons, Yasufuku sired cattle had a longissimus muscle fatty acid composition that was more desirable compared with Angus sired cattle, while Fukutsuru sired cattle were typically intermediate. As demonstrated in the first study, there is considerable variation within sire breed, and sire selection should be based on desirable traits rather than breed alone. Gene expression results may indicate periods of pre-adipocyte proliferation and lipid filling for steers in the present study, with two critical windows at approximately 7 and 17 months of age for marbling development. Genes responsible for vascular development and growth may indicate greater blood vessel development around 7 to 8 months of age, with continuous branching until 15 to 16 months of age. The upregulation of lipogenic genes was initiated around 12 months of age and peaked at 14 months of age, while lipolytic genes expression was upregulated shortly after 14 months of age. The gene expression results of Yasufuku sired cattle exhibited random peaks that may be responsible for preadipocyte proliferation compared

iii with Angus and Fukutsuru sired cattle. Future research can be conducted to develop feeding strategies to increase energy availability during critical marbling development times (7 and 17 months of age), while restricting energy intake during other times, which may allow producers to reduce feed costs without reducing marbling potential. As demonstrated in the first study, there is considerable variation within sire breed, and sire selection should be based on desirable traits rather than breed alone.

Vita

August, 2013 ……………… B.S. Animal Sciences, University of Wisconsin-River Falls

December, 2016 …………... M.S. Animal Sciences, The Ohio State University

January, 2017 to present ….. Graduate Research Associate, Department of Animal

Sciences, The Ohio State University

Publications

Jaborek, J. R., Zerby, H. N., Moeller, S. J., Fluharty, F. L., Relling, A. E. 2019.

Evaluation of feedlot performance, carcass characteristics, carcass retail cut

distribution, Warner-Bratzler shear force, and fatty acid composition of crossbred

Jersey steers and heifers. Appl. Anim. Sci.

Jaborek, J. R., Zerby, H. N., Moeller, S. J., Fluharty, F. L., Relling, A. E. 2019.

Evaluation of feedlot performance, carcass characteristics, carcass retail cut

distribution, Warner-Bratzler shear force, and fatty acid composition of purebred

Jersey and crossbred Jersey steers. Transl. Anim. Sci. 3: 1475–1491.

Jaborek, J. R., Zerby, H. N., Moeller, S. J., Fluharty, F. L, Garza III, H., Garcia, L. G.,

England, E. M. 2018. Effect of energy source and level, and animal age and sex

on meat characteristics of sheep. Small Rumin. Res. 166: 53-60. v

Jaborek, J. R., Zerby, H. N., Moeller, S. J., Fluharty, F. L. 2018. Effect of energy source

and level, and sex on growth, performance and carcass characteristics of long-fed

lambs. Small Rumin. Res. 167: 61-69.

Jaborek, J. R., Zerby, H. N., Moeller, S. J., Fluharty, F. L. 2017. Effect of energy

source, level, and sex on growth, performance, and carcass characteristics of

lambs. Small Rumin. Res. 151: 117-223.

Jaborek, J. R., Lowe, G. D., Fluharty, F. L. 2016. Effects of pen flooring type and

bedding on lamb growth and carcass characteristics. Small Rumin. Res. 144: 28-

34.

Fields of Study

Major Field: Animal Sciences

Table of Contents

Abstract ...... ii Vita ...... v List of Tables ...... xi List of Figures ...... xiii Chapter 1. Introduction ...... 1 Chapter 2. Literature Review ...... 4 Adipose structure and function ...... 4 Origin and development of adipose tissue ...... 4 Adipocyte development (Adipogenesis) ...... 6 Determination / Commitment ...... 6 Confluence & Mitogenic expansion ...... 10 Differentiation ...... 11 Effect of different cattle breeds on marbling ability and carcass value ...... 16 Chapter 3. Evaluation of Feedlot Performance, Carcass Characteristics, Carcass Retail Cut Distribution, Warner-Bratzler Shear Force, and Fatty Acid Composition of Purebred Jersey and Crossbred Jersey Steers ...... 20 ABSTRACT ...... 20 INTRODUCTION ...... 21 MATERIALS AND METHODS ...... 23 Animals and treatments ...... 23 Feeding and management ...... 23 Carcass fabrication ...... 24 Warner-Bratzler shear force ...... 25 Longissimus fatty acid composition ...... 25 Statistical Analysis ...... 26

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RESULTS AND DISCUSSION ...... 27 Feedlot Performance ...... 27 Carcass Characteristics ...... 29 Carcass Cut-Out Distribution ...... 32 Warner-Bratzler shear force ...... 36 Longissimus fatty acid composition ...... 38 Value-added potential ...... 39 Implications...... 42 LITERATURE CITED ...... 43 Chapter 4. Evaluation of feedlot performance, carcass characteristics, carcass retail cut distribution, Warner-Bratzler shear force, and fatty acid composition of crossbred Jersey steers and heifers ...... 58 ABSTRACT ...... 58 INTRODUCTION ...... 59 MATERIALS AND METHODS ...... 60 Animals and treatments ...... 60 Feeding and management ...... 60 Carcass fabrication ...... 61 Warner-Bratzler shear force ...... 62 Longissimus muscle fatty acid composition ...... 62 Statistical Analysis ...... 63 RESULTS AND DISCUSSION ...... 64 Feedlot Performance ...... 64 Carcass Characteristics ...... 65 Carcass Cut-Out Distribution ...... 68 Warner-Bratzler shear force ...... 72 Fatty acid composition ...... 73 APPLICATIONS ...... 75 LITERATURE CITED ...... 76 Chapter 5. Opportunities to improve the accuracy of the United States Department of Agriculture beef yield grade equation through precision agriculture ...... 90 ABSTRACT ...... 90 INTRODUCTION ...... 91

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MATERIALS AND METHODS ...... 92 RESULTS & DISCUSSION ...... 94 Implications...... 99 LITERATURE CITED ...... 100 Chapter 6. Comparison of feedlot performance, carcass characteristics, and fatty acid composition of Angus- and Wagyu-sired cattle when raised to a similar age or body weight ...... 106 ABSTRACT ...... 106 INTRODUCTION ...... 107 MATERIALS AND METHODS ...... 108 Experiment 1 treatments ...... 108 Experiment 2 treatments ...... 108 Feeding and management ...... 109 Carcass data collection ...... 110 Longissimus fatty acid composition ...... 110 Statistical Analysis ...... 110 RESULTS AND DISCUSSION ...... 111 Experiment 1 (constant age and days on feed comparison) ...... 111 Experiment 2 (constant body weight comparison) ...... 117 Summary ...... 121 Implications...... 122 LITERATURE CITED ...... 124 Chapter 7. Lipid metabolism gene expression of the Longissimus muscle from Angus- and Wagyu-sired cattle when raised to a similar age or body weight ...... 134 ABSTRACT ...... 134 INTRODUCTION ...... 135 MATERIALS AND METHODS ...... 136 Experiment 1 treatments ...... 136 Experiment 2 treatments ...... 136 Management, feeding, and biopsy collection ...... 136 RNA extraction and analysis ...... 138 Statistical Analysis ...... 138 RESULTS AND DISCUSSION ...... 139

Adipogenic gene expression ...... 139 Lipogenic gene expression ...... 141 Angiogenic gene expression ...... 143 Fatty acid uptake and transport gene expression ...... 145 Lipolytic gene expression ...... 146 Implications...... 148 LITERATURE CITED ...... 149 Chapter 8. Conclusion ...... 192 Bibliography ...... 195

List of Tables

Table 1. Composition of diets offered during the experiment ...... 49 Table 2. Effect of terminal sire breed on the feedlot performance of purebred and crossbred Jersey steers adjusted to a similar initial body weight (210 kg) ...... 50 Table 3. Effect of sire breed on carcass characteristics of purebred and crossbred Jersey steers adjusted to a similar hot carcass weight (319 kg) ...... 51 Table 4. Effect of sire breed on the distribution of carcass weight into retail cuts from purebred and crossbred Jersey steers adjusted to a similar chilled carcass side weight (154 kg) ...... 53 Table 5. Effect of sire breed on the fatty acid composition (%) of the longissimus muscle from purebred and crossbred Jersey steers ...... 57 Table 6. Composition (%) of diets offered during the experiment on a DM basis ...... 81 Table 7. Effect of terminal sire breed on the feedlot performance of crossbred Jersey steers and heifers adjusted to a similar initial BW (203 kg) ...... 82 Table 8. Effect of terminal sire breed on carcass characteristics of crossbred Jersey steers and heifers adjusted to a similar HCW (319 kg) ...... 83 Table 9. Effect of sire breed on the distribution of carcass weight into retail cuts from crossbred Jersey steers and heifers adjusted to a similar chilled carcass side weight (154 kg) ...... 86 Table 10. Effect of sire breed on the fatty acid composition of the LM from purebred and crossbred Jersey steers and heifers ...... 89 Table 11. Comparison between current USDA regression equations for boneless closely trimmed retail cuts and yield grade and newly proposed regression equations for Jersey influenced cattle ...... 103 Table 12. Linear regression equation for the prediction of percent boneless closely trimmed retail cuts and yield grade of Jersey influenced cattle from the USDA percent boneless closely trimmed retail cuts and yield grade...... 104 Table 13. Reduced equations of newly proposed boneless closely trimmed retail cut and yield grade regressions for Jersey influenced cattle ...... 105 Table 14. Composition (%) of diets offered during the experiment on a dry matter basis ...... 127 Table 15. Feedlot performance of Angus- and Wagyu-sired cattle raised to a similar age and days on feed endpoint ...... 128 Table 16. Carcass characteristics of Angus- and Wagyu-sired cattle with a similar age and days on feed endpoint ...... 129 Table 17. Longissimus muscle fatty acid composition (%) of Angus- and Wagyu-sired cattle with a similar age and days on feed endpoint ...... 130 xi

Table 18. Feedlot performance of Angus- and Wagyu-sired cattle raised to a similar body weight endpoint ...... 131 Table 19. Carcass characteristics of Angus- and Wagyu-sired cattle raised to a similar body weight endpoint ...... 132 Table 20. Longissimus muscle fatty acid composition (%) of Angus- and Wagyu-sired cattle raised to a similar body weight endpoint ...... 133 Table 21. Composition (%) of diets offered during the experiment on a dry matter basis ...... 151 Table 22. List of genes analyzed from longissimus muscle tissue of Angus- and Wagyu- sired steers ...... 152

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List of Figures

Figure 1. Effect of sire breed and postmortem aging period on the Warner-Bratzler shear force of the longissimus muscle from purebred and crossbred Jersey steers. SimAngus and Wagyu sired steers produced more (P ≤ 0.01) tender steaks compared to Angus and Jersey sired steers. Postmortem aging improved (P ≤ 0.01) steak tenderness from 7 to 14 days. The standard error of the mean (SEM) for the interaction between sire breed and postmortem aging was 0.213 kg...... 56 Figure 2. Effect of postmortem aging period on the Warner-Bratzler shear force of the LM from crossbred Jersey cattle. Postmortem aging lsmean estimates with a different superscript differ (P ≤ 0.01)...... 85 Figure 3. Three relationships between percent boneless closely trimmed retail cuts (BCTRC) and USDA yield grade (YG) of purebred and crossbred Jersey cattle. The relationship between the calculated percent BCTRC and calculated USDA YG (●) is plotted in the upper left corner and follows the relationship Y = -2.3x + 56.9. The relationship between the actual percent BCTRC and calculated USDA YG (○) is plotted in the bottom left corner and follows the relationship Y = -1.29x + 39.6 (R2 = 0.22). The relationship between the actual percent BCTRC and actual USDA YG (▲) is plotted in the bottom right corner and follows the relationship Y = -2.3x + 56.9...... 102 Figure 4. Expression of zinc finger protein 423 (ZFP423) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 154 Figure 5. Expression of prostacyclin synthase (PTGIS) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 155 Figure 6. Expression of cAMP responsive element binding protein 1 (CREB1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05)...... 156 Figure 7. Expression of CCAAT enhancer binding protein beta (CEBPb) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at xiii a given biopsy with a () differ (P ≤ 0.05). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 157 Figure 8. Expression of peroxisome proliferator activated receptor delta (PPARd) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05)...... 158 Figure 9. Expression of CCAAT enhancer binding protein alpha (CEBPa) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 159 Figure 10. Expression of peroxisome proliferator activated receptor gamma (PPARg) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05)...... 160 Figure 11. Expression of sterol regulatory element binding transcription factor 1 (SREBF1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05)...... 161 Figure 12. Expression of ATP citrate lyase (ACLY) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 162 Figure 13. Expression of acetyl-CoA carboxylase 1 (ACAC1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 163 Figure 14. Expression of acetyl-CoA carboxylase 2 (ACAC2) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05)...... 164 Figure 15. Expression of fatty acid synthase (FASN) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a

xiv similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 165 Figure 16. Expression of fatty acid elongase 6 (ELOVL6) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 166 Figure 17. Expression of stearoyl-CoA desaturase (SCD) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 167 Figure 18. Expression of glycerol-3-phosphate dehydrogenase 1 (GPD1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 168 Figure 19. Expression of glycerol-3-phosphate acyltransferase (GPAM) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05)...... 169 Figure 20. Expression of 1-acylglycerol-3-phosphate O-acyltransferase 1 (AGPAT1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 170 Figure 21. Expression of lipin 1 (LPIN1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05)...... 171 Figure 22. Expression of diacylglycerol O-acyltransferase 1 (DGAT1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 172 Figure 23. Expression of vascular endothelial growth factor (VEGF) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 173 Figure 24. Expression of angiopoietin 1 (ANGPT1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a xv similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05)...... 174 Figure 25. Expression of angiopoietin 2 (ANGPT2) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 175 Figure 26. Expression of platelet derived growth factor alpha (PDGFA) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 176 Figure 27. Expression of platelet derived growth factor beta (PDGFB) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 177 Figure 28. Expression of lipoprotein lipase (LPL) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 178 Figure 29. Expression of low density lipoprotein receptor (LDLR) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05)...... 179 Figure 30. Expression of scavenger receptor class B member1 (SCARB1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 180 Figure 31. Expression of cd36 molecule (CD36) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 181 Figure 32. Expression of solute carrier family 27 member 1 (SLC27A1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05)...... 182 xvi

Figure 33. Expression of fatty acid binding protein 4 (FABP4) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 183 Figure 34. Expression of diazepam binding inhibitor (DBI) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05)...... 184 Figure 35. Expression of peroxisome proliferator activated receptor alpha (PPARA) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 185 Figure 36. Expression of peroxisome proliferator activated receptor coactivator 1 alpha (PPARGC1A) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 186 Figure 37. Expression of patatin like phospholipase domain containing 2 (PNPLA2) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05)...... 187 Figure 38. Expression of hormone sensitive lipase (HSL) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05)...... 188 Figure 39. Expression of monoglyceride lipase (MGL) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05)...... 189 Figure 40. Expression of carnitine palmitoyltransferases 1 (CPT1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05)...... 190

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Figure 41. Expression of very long chain acyl-CoA dehydrogenase (ACADVL) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05)...... 191

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Chapter 1. Introduction

Marbling, also known as intramuscular fat (IMF), can be visually recognized as the deposition of fat between the muscle fibers within the muscle bundles of the muscle (Moody and Cassens, 1968). In the U.S., the USDA can award beef carcasses a quality grade (QG) indicative of eating satisfaction, and a yield grade (YG) indicative of retail yield (USDA, 2016). Similar to other countries that use marbling as an indicator of beef quality, the USDA QG is based on a marbling score and carcass maturity. A beef carcass with a greater degree of marbling and a younger carcass maturity will receive a higher quality grade and is more valuable. Fat deposition in other areas of the carcass will result in a reduced carcass yield, because excess subcutaneous and intermuscular fat will need to be trimmed and contribute to a reduced yield and lower carcasses value. Meat eating quality is influenced by three sensory characteristics: tenderness, juiciness, and flavor. Consumer acceptability of beef tenderness, juiciness, and flavor increase with an increasing level of marbling (May et al., 1992; Platter et al., 2003; Killinger et al., 2004). Tenderness is improved with a greater degree of marbling because the deposition of IMF infiltrates and breaks apart the collagen cross-linking responsible for the toughness of meat (Nishimura et al., 1999). The replacement of lean muscle with IMF also provides a “background” tenderness effect because fat is less dense than muscle tissue. Greater amounts of marbling provide lubrication during cooking and chewing, resulting in greater juiciness (Frank et al., 2016). Fat is responsible for the majority of the volatile flavor compounds released during cooking and experienced during eating (Frank et al., 2016). For these reasons, eating quality and consumer satisfaction are heavily dependent on the degree of marbling within the beef carcass. Even though marbling has been shown to improve sensory characteristics important for eating satisfaction, consumers still prefer to buy leaner cuts of meat at the

1 grocery store (Killinger et al., 2004). Many consumers choose to select for leaner cuts of meat because they think fat is unsightly, unhealthy, or simply do not want to pay for fat. However, consumer taste panels demonstrate that consumers consistently award greater overall acceptability scores for meat with greater marbling scores. Therefore, the typical consumer is unaware of indicators for meat quality (i.e. marbling) which can result in poor consumer satisfaction of their purchased meat product (Grunert et al., 2004). Consumers need to be taught that the fat within the muscle (i.e. IMF) is beneficial and can improve the eating experience whereas back fat (subcutaneous) and seam fat (intermuscular) are less desirable and reduce yield. Red meat is very nutrient dense and the consumption of red meat, such as beef, is a great source of bioavailable minerals (zinc, iron, selenium, phosphorus, magnesium, potassium, and copper) and vitamins (B1, B2, B5, B6, and B12) when compared with plant sources (Troy et al., 2016). Since health agencies condemned fat consumption and promoted eating low fat diets in the 1970s there has been an increased incidence of obesity. As a partial result, obesity has developed into a global pandemic over the past 50 years, in part, due to the substitution of fat for carbohydrates in the diet (Smith et al., 2016). Recent work from S. B. Smith’s lab at Texas A&M (Adams et al., 2010; Gilmore et al., 2011; Gilmore et al., 2013; Crouse et al., 2016) has shown that the consumption of beef high in oleic acid (C18:1n-9) can have health related benefits by increasing plasma high density lipoprotein – cholesterol (HDL) and by decreasing plasma low density lipoprotein cholesterol (LDL). Smith et al. (2016) have reported that as cattle grow and increase in age, their fatty acid composition includes greater concentrations of oleic acid. Oleic acid also has a positive relationship with marbling content of beef (Smith et al., 2016). Higher marbling breeds of cattle, such as Wagyu and Hanwoo, typically have greater concentrations of monounsaturated fatty acids (MUFA), such as oleic acid, and polyunsaturated fatty acids (PUFA), with less saturated fatty acids (SFA) compared to lower marbling breeds (Gotoh and Joo, 2016). The consumption of MUFA and PUFA in the diet of humans has also been reported to increase satiety compared to SFA, which may help limit food consumption for consumers of beef (Maljaars et al., 2009).

Therefore, by increasing marbling content of beef we can provide a product that is more nutrient dense, with a greater eating satisfaction, and positive health benefits. Since its induction in 1995, the National Beef Quality Audit (NBQA) has reported an increase in the occurrence of elevated marbling scores in harvested fed cattle. Greater marbling scores are partially due to greater hot carcass weights along with fatter carcasses. A 6.4% increase in the number of dairy-type cattle harvested was reported in the 2016 audit (16.3%) compared with the 2011 audit (9.9%), and of the cattle that received a Prime QG, 32% were dairy-type cattle (Boykin et al., 2017). The 2016 NBQA (Boykin et al., 2017) recently reported 75% of the fed cattle are achieving a marbling score of small or greater, a 10% increase from the 2011 NBQA (Moore et al., 2012). However, a large proportion (40%) of the fed cattle in the U.S. are receiving a marbling score of small. A marbling score of small with A carcass maturity would receive a Low Choice QG. As a result, approximately 55% of the beef carcasses in the U.S. are receiving discounts due to a lack of marbling. As a leading country of producing high quality beef, there is a considerable amount of room for improving the marbling deposition of cattle in the U.S.

Chapter 2. Literature Review

Adipose structure and function

Adipose tissue is made up of a complex matrix of vasculature and connective tissue comprised of numerous different cell types including adipocytes, endothelial cells, macrophages, and mast cells. The primary purpose and function of white adipose tissue is to regulate energy homeostasis. During periods of positive energy balance or in a fed state, the adipose tissue undergoes lipogenesis, which is the synthesis and storage of triglycerides inside adipocytes. When energy is needed as fuel or the body is in a fasted state, the adipose tissue undergoes lipolysis, which is the breakdown of triglycerides for the transport of fatty acids into the body’s circulation to be used for energy. Adipocyte cell type (white, brown, beige) can affect the functionality of the adipose tissue as well. White adipose tissue stores fat as unilocular lipid droplets. While brown adipocytes store lipid as smaller multilocular droplets that can be used for thermogenesis. The adipose tissue also acts as a functional endocrine organ that can secrete hormones, growth factors, enzymes, and cytokines in the body. Due to complexity of this organ, many new discoveries regarding its function are being made, but questions remain about the developmental signaling cascade leading to the development and growth of adipose tissue. Origin and development of adipose tissue

Very few studies have investigated the ontogeny of adipose tissue in depth, especially with a focus on various fat depots found within the body of cattle. Although, it is commonly recognized that the ontogeny of adipose tissue is relatively conserved across mammalian species, with adipose tissue beginning to appear by mid-gestation and an increase in adipose tissue mass throughout the remainder of late gestation (Symonds et al., 2012). Bell (1909) reported fat droplets in a 7 cm long bovine fetus throughout the body near blood vessels and between muscle fibers. The observation of fat droplets in muscle fibers and in between muscle fibers at such an early stage of development may be

4 used in energy metabolism for the development of other tissues rather than as energy storage (Bell, 1909). Vernon (1980) states that pre-adipocytes can be found in the perirenal (kidney fat) tissue of the lamb fetus during the second month of gestation, while lipid accumulation begins during the third month of gestation. White adipose tissue continues to accumulate after mid-gestation, however the amount of white adipose tissue appears to decrease shortly before birth (Vernon, 1986). The decrease in white adipose tissue before birth coincides with a rapid accumulation of brown adipose tissue around the time of birth (Cornelius et al., 1994). This rapid change in adipose tissue prepares the newborn to use its energy stores to regulate its own body temperature to survive outside the uterus of the mother in a harsher environmental condition. It was once thought that adipose tissue accretion only occurred by hypertrophic growth similar to muscle accumulation, with cell number fixed by birth. However, Hood and Allen (1973) observed an increase in adipocyte number, representing hyperplastic growth. Robelin et al. (1981) reported that cell number did not increase in intermuscular fat, but subcutaneous fat demonstrated hyperplastic growth with an increased adipocyte number from 15-35% and 45-65% mature body weight. Therefore, hyperplasia of adipocytes in the intermuscular and visceral fat depots begin to occur during early- to mid-gestation until the early postnatal stage. While the formation of subcutaneous adipocytes occurs later, between mid-gestation until shortly after weaning age (~8 mo.) (Hood and Allen, 1973). However, the formation/proliferation of intramuscular adipocytes during fetal development is unknown. Some speculate the intramuscular fat depot develops during late gestation or the early neonatal stage (Du et al., 2010) and continues to proliferate throughout the finishing phase (Schoonmaker et al., 2004; Pickworth et al., 2011) and at least up to at least 19 mo. of age (Cianzio et al., 1985). Intermuscular fat in cattle contributes about 35% of the total body fat near birth, increases to 45-50% before weaning and remains relatively constant throughout life (Johnson et al., 1972). Subcutaneous fat contributes significantly less to total body fat in cattle near birth (5%), but increases rapidly until plateauing around 30% shortly after reaching weaning age (+252 d; Johnson et al., 1972). Intramuscular fat and visceral fat

5 contribute approximately 25% and 33%, respectively, in the 210 d bovine fetus and shortly after birth, but their relative contribution to total body fat decreases to approximately 10% in each depot after a year of age (Johnson et al., 1972). Strategies to shift energy utilization to the muscle and intramuscular fat depot relative to other fat depots will result in an improved efficiency of energy utilization for the growth of saleable high quality beef. Adipocyte development (Adipogenesis)

Adipose tissue can grow and accumulate through two mechanisms: hyperplasia and hypertrophy. Hyperplastic growth in adipocytes results in an increased cell number through cellular proliferation and clonal division. Hypertrophic growth of adipocytes is an increase in cell size as the result of lipid filling by incorporating triglycerides into the adipocyte. The developmental progression of mesenchymal progenitor cells into mature adipocytes is referred to as adipogenesis. Adipogenesis begins with the commitment or determination of mesenchymal stem cells to the adipose tissue lineage and formation of fibro/adipogenic progenitor cells, also known as preadipocytes. With appropriate cellular signals, preadipocytes begin to proliferate until they reach confluence in vitro. Upon reaching confluence, preadipocytes undergo a stage of growth arrest before being signaled to begin mitotic clonal expansion. Adipogenic signals trigger the conversion or differentiation of preadipocytes into mature adipocytes through the incorporation and storage of triglycerides into the adipocyte. Determination / Commitment

Unlike muscle, no regulatory gene or determination factor has been identified for the commitment of fibro/adipogenic progenitor cells to the adipogenic lineage (Cornelius et al., 1994). It is believed preadipocytes develop from a distinctively different progenitor cell when compared with myocytes (Joe et al., 2010; Uzemi et al., 2010); with fibroblasts and white adipocytes developing from cells failing to express myogenic regulatory factor 5 (Mrf5) and paired box 7 (Pax7) like myocytes and brown adipocytes (Wang and Seale, 2016).

The majority of the knowledge about adipogenesis has been attained through the use of in vitro cell cultures. Cell culture work has been completed through either primary cell cultures or already established preadipocyte lines (i.e. 3T3-L1 cells). In primary cell cultures, preadipocytes are typically found or isolated from the stromal vascular portion of pre-existing adipose tissue consisting of a heterologous assortment of cell types, such as pericytes, macrophages, endothelial cells, and preadipocytes (Berry et al., 2013; Hudak and Sul, 2013). Current preadipocyte markers are not without their doubts; therefore, identification of a marker specific to preadipocytes has proven difficult (Berry et al., 2014). Preadipocyte factor 1 (Pref-1), also known as delta like homolog-1 (DLK-1), is an extracellular transmembrane bound protein that becomes biologically active when spliced and allowed to interact with fibronectin (Hudak and Sul, 2013). The interaction between Pref-1 and fibronectin cause the MEK/ERK pathway to be activated and the induction of Sox9 expression. The induction of Sox9 expression causes it to bind to the promotor regions of CCAAT/ enhancer binding protein (C/EBP) β and δ, thus blocking the initiation of adipogenic differentiation. The initiation of differentiation of preadipocytes into adipocytes is caused by the transient expression of Pref-1. In preadipocytes, Pref-1 expression is high, and in order for differentiation to initiate, Pref-1 expression needs to be abated to allow for the expression of C/EBP β and δ to induce other adipogenic genes, such as PPARγ and C/EBPα (Campos et al., 2016). The number of cells per area expressing Pref-1 is much greater in neonatal calves when compared to 18 month old cattle (Albrecht et al., 2015). However, the number of cells per area expressing Pref-1 did increase slightly from 18-26 months of age in Holstein cattle, with no differences in Japanese Black cattle. Cells positively expressing Pref-1 were found surrounding muscle fibers or within adipose or connective tissue of the muscle. The expression of Pref-1 can vary between fat depots and cattle breeds (Albrecht et al., 2015; Yamada et al., 2014), with Japanese Black cattle having a lower expression of Pref-1 in intramuscular, perineal, and mesenteric fat depots, no difference in the subcutaneous fat depot, and greater Pref-1 expression in the intermuscular and visceral

7 fat depots when compared with Holstein cattle. The greater expression of Pref-1 in the Longissimus muscle observed in Holstein cattle when compared with Japanese Black cattle, along with Pref-1’s ability to inhibit C/EBP β, may be the reason for greater marbling accumulation for Japanese Black cattle (Albrecht et al., 2011). Even though both breeds of cattle expressed similar levels of C/EBP β, as shown by the negative relationship (r = -0.80) between intramuscular fat percentage and the number of cells expressing Pref-1 in the experiment conducted by Albrecht et al. (2015). Uezumi et al. (2011) demonstrated that greater than 90% of cells expressing platelet derived growth factor receptor α (PDGFRα) and lacking cell surface receptors CD31 and CD45 in skeletal muscle were fibro/adipogenic precursor cells. The expression of transforming growth factor β (TGF-β1) in these same PDGFRα+ fibro/adipogenic precursor cells can give rise to collagen formation, while adipogenic medium promotes adipogenesis. These results suggest a common mesenchymal precursor for collagen and adipose development distinct of muscle formation (Uezumi et al., 2011). Sorting of bovine stromal vascular (SV) cells expressing PDGFRα with high and low adipogenic potential have demonstrated greater expression of zinc finger protein 423 (ZFP423) and lower expression of TGF-β1 in highly adipogenic cells, while cells with low adipogenic potential expressed low ZFP423 and high TGF-β1 (Huang et al., 2012). Gupta et al. (2010) have shown that ZFP423 helps regulate the expression of peroxisome proliferator activating-receptor γ (PPARγ), which promotes adipogenic differentiation of preadipocytes into mature adipocytes. The SMAD domain on the ZFP423 gene is not necessary to promote PPARγ expression, but is crucial for the pro- adipogenic effect caused by bone morphological proteins (BMP), BMP4 in particular (Gupta et al., 2010). Huang et al. (2012) have also demonstrated that knock-down of ZFP423 hindered adipogenesis in SV cells, while over-expression of ZFP423 in SV cells with low adipogenic potential were able to reach a level of adipogenesis similar to SV cells with high adipogenic potential and inhibit the expression of TGF-β1. Huang et al.

(2012) have shown that DNA methylation of ZPF423 and TGF-β1 regulates their expression and the potential for adipogenesis to occur. Expression and protein content of ZFP423 in primary bovine SV cells obtained from subcutaneous adipose was not different before differentiation, after 6 days of differentiation, or in adipose tissue when compared between Angus and Wagyu cattle (Wei et al., 2015). Expression of ZFP423 can differ between fat depots, as ZFP423 expression appeared to be greater in visceral fat when compared with the subcutaneous fat depot (Gupta et al., 2012). Differential expression of ZFP423 between fat depots means there could be potential differences for ZFP423 expression in cells located in muscle as well. Wagyu cattle have reportedly greater expression of ZFP423 compared to Angus cattle at 24 months of age in the muscle (Duarte et al., 2013). A greater expression of ZFP423 likely led to a greater PPARγ expression and the development of more intramuscular fat in Wagyu cattle when compared with Angus cattle (Duarte et al., 2013). Fu et al. (2017) demonstrated that skeletal muscle derived cells from Wagyu cattle expressed higher levels of ZFP423 and PPARγ compared with Angus cattle when differentiated in adipogenic medium for 14 days. The use of ZFP423 as a preadipocyte marker in subcutaneous and visceral fat depots revealed that cell surface markers (i.e. Sca1 and CD24) can be different between fat depots (Gupta et al., 2012). Gupta et al. (2012) also demonstrated that ZFP423+ preadipocytes reside in the adipose vasculature as a subset of pericytes and endothelial cells, but not in the skeletal muscle vasculature in the embryo. However, this finding doesn’t rule out the potential for ZFP423 expression in pericytes or endothelial cells of the skeletal muscle vasculature at a later time period as the animal matures. Interestingly, Duarte et al. (2013) reported greater expression of two inhibitors of adipogenic differentiation (fibronectin and TGF-β1) in muscle samples from 24 month old Wagyu cattle compared with Angus cattle, with fibronectin interacting with Pref-1 and TGF- β1 inhibiting ZFP423 expression. Greater expression of these two proteins would inhibit differentiation from occurring; however, it may be that fibronectin is

9 creating an extracellular matrix suitable for new preadipocytes to develop into mature adipocytes. Confluence & Mitogenic expansion

Once fibro/adipogenic progenitor cells have committed to the adipogenic lineage, they undergo proliferation. Proliferation of these preadipocytes continues until the cells exhibit cell to cell contact, otherwise known as confluence, in vitro. At confluence, preadipocytes have increased lipoprotein lipase (LPL), type VI collagen, and PPARδ (Cornelius et al., 1994; MacDougald and Lane, 1995; Smas and Sul, 1995). Cell to cell contact seems necessary for mitotic clonal expansion and the initiation of the differentiation process to occur, which may be due to the changes taking place in the extracellular matrix (ECM; Kubo et al., 2000). Kubo et al. (2000) reported that fibronectin was the first ECM protein examined to develop and degrade during the progression of adipogenesis. After preadipocytes reach confluence and growth arrest, they go through mitotic divisions during clonal expansion that appear necessary for differentiation to proceed (MacDougald and Lane, 1995; Smas and Sul, 1995). Fibroblast growth factor (FGF) and PDGF are mitogens that help stimulate several rounds of post-confluent mitosis, but their expression disappears before differentiation (Cornelius et al., 1994; MacDougald and Lane, 1995). The expression of cell cycle regulators, c-myc, c-fos, c-jun, and fra-1 occurs during mitogenesis, but their expression needs to be switched off for differentiation to initiate. Activator protein-1 (AP-1) is a heterodimer transcription factor made up of c-fos and c-jun proteins. Expression of AP-1 in preadipocytes appears to acts as a switch between mitotic expansion and differentiation because expression of AP-1 inhibits the expression of fatty acid binding protein 4 (FABP4), a sign of lipid accumulation and differentiation of preadipocytes into adult adipocytes (Distel et al., 1987; Angel and Karin, 1991). Interestingly, the expression of FABP4 is not inhibited by AP-1 in mature adipocytes however. Huang et al. (2017) reported up-regulated expression of differentially expressed genes (fos) associated with AP-1 from Wagyu

10 cattle subcutaneous adipose tissue when compared with subcutaneous adipose tissue from Holstein cattle with significantly less subcutaneous fat. Wagyu SV cells have a greater ability to proliferate in vitro when compared with Angus SV cells, while Angus SV cells were more responsive to external mitogenic stimuli (FGF2) compared to SV cells from 12 month old Wagyu heifers (Wei et al., 2015). Wagyu SV cells also had greater phosphorylation (activation) of ERK1/2 and numerically greater phosphorylation of protein kinase B (PKB) compared to SV cells from Angus cattle, while again Angus SV cells were more responsive to FGF2 stimulation to cause greater phosphorylation of ERK1/2 compared to Wagyu SV cells (Wei et al., 2015). Interestingly, Angus SV cells expressed greater levels of FGF2 and similar amounts of FGFR1 compared to Wagyu SV cells from subcutaneous fat obtained from 12 month old heifers (Wei et al., 2015). In contrast, Duarte et al. (2013) attributed greater adipocyte proliferation in muscle tissue samples from 24 month old Wagyu steers because of greater levels of FGF2 and FGFR1 when compared with Angus steers. Adipose tissue cell cultures from cattle on a low energy diet for 552 days have shown a nearly 2-fold greater proliferative ability (increase in DNA synthesis) in lipid-filling and SV cells from crossbred Wagyu (3/4- & 7/8-blood) when compared with Angus through greater thyimidine incorporation into DNA (May et al., 1994). Differentiation

The use of an adipogenic cocktail, made up of a combination of dexamethasone (DEX), isobutylmethylxanthine (IBMX), insulin, and occasionally fetal bovine serum (FBS) is used depending on the type of cell culture grown to stimulate preadipocytes to differentiate (Cornelius et al., 1994; Smas and Sul, 1995; Farmer, 2006). The compounds that make up the adipogenic cocktail target the signaling transduction pathways believed to regulate adipogenesis (Cornelius et al., 1994; MacDougald et al., 1995; Smas and Sul, 1995; Gregoire et al., 1998). Dexamethasone is a glucocorticoid that can act as a ligand for PPARγ activation and upregulate the differentiation of preadipocytes into adult adipocytes. The inclusion of IBMX, a cAMP phosphodiesterase inhibitor, would allow for a sustained activation of kinases such as protein kinase A (PKA), to activate 11 transcription factors to promote differentiation as well. While insulin would activate the insulin like growth factor receptor-1 pathway, stimulating PKB and upregulate glucose uptake. The pattern of adipogenic differentiation can be thought of as occurring in two waves of transcription factors, early and late, that promote adipogenic differentiation. However, even before the induction of differentiation with the adipogenic cocktail in vitro, CCAAT enhancer binding proteins (C/EBP) β and δ are expressed in preadipocytes and become more active during mitotic clonal expansion (Tang et al., 2003). C/EBPβ has two different splicing forms liver-enriched activator protein (LAP) and liver-enriched inhibitor protein (LIP), with LAP being able to restore mitotic clonal expansion in C/EBPβ null mice (Tang et al., 2003). C/EBPβ is able to bind to relatively small, inaccessible areas of chromatin on the DNA, allowing for binding and the induction and recruitment of other transcription factors to DNA binding “hot spots” (Sierbaek et al., 2012; Lefterova et al., 2014). C/EBPβ recruits other early transcription factors such as glucocorticoid receptor (GR), signal transducer and activator of transcription (STAT5A), Kruppel-like factors (KLFs), cAMP response element binding protein (CREB), early growth factor 2 (KROX20), retinoid X receptor (RXR) and sterol regulatory element- binding protein (SREBP-1c) (Siersbaek et al., 2012). Since extensive chromatin remodeling occurs during the initiation of differentiation and C/EBPβ binds to many PPARγ binding sites before PPARγ even binds, it has been suggested that C/EBPβ may assist chromatin remodeling to prepare for PPARγ binding for terminal differentiation (Siersbaek et al., 2012). The early differentiation transcription factors (i.e. C/EBPβ) activate PPARγ and C/EBPα through C/EBP binding sites in their respective promotor regions to terminally differentiate preadipocytes into adult adipocytes (Tang et al., 2003). Up-regulation of C/EBPα is believed to help terminate clonal expansion and promote terminal differentiation (Cornelius et al., 1994). Activation of PPARγ is caused by ligand binding of fatty acids, prostaglandins, and other fatty acid derivatives; however, a potent ligand present in vivo hasn’t been identified. The expression of SREBP-1c occurs later during

12 adipogenesis and can transcribe fatty acid synthesis genes, which can lead to the production of endogenous PPARγ ligands. PPARγ also forms a heterodimer with the retinoid x receptor (RXRα) to promote its transcription of genes (Tontonoz et al., 1994a; 1994b). The RXR transcription factor can also form heterodimer complexes with retinoic acid receptor (RAR) and vitamin D receptor (VDR), which can inhibit RXR from forming a heterodimer with PPARγ. The PPARγ2 isoform has previously been recognized as the primary PPARγ isoform in adipose tissue (Tontonoz et al., 1994a). The expression of PPARγ and C/EBPα leads to the activation of other genes associated with lipid and glucose metabolism. In contrast with other reports mentioned earlier, Tontonoz et al. (1994a) reported that PPARγ induces LPL expression in adipocytes. Interestingly, co-locolization of PPARγ and C/EBPα has been reported to happen at 35-60% of chromatin binding sites on the DNA (Lefterova et al., 2014); however, not much is yet known about what this synergistic relationship means for the progression of adipogenic differentiation. Since differentiation is the process of preadipocytes accumulating lipid, de novo lipogenesis is heavily up-regulated during differentiation. Therefore, increased activities of mRNAs and proteins for ATP citrate lyase (ACL), malic enzyme (ME), acetyl-CoA carboxylase (ACC), steroyl-CoA desaturase (SCD), glycerol phosphate acyltransferase (GPAT), glycerol-3-phosphate dehydrogenase (GPDH), fatty acid synthase (FASN), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) are observed (Smas and Sul, 1995). PPARγ and C/EBPα activate αP2 (also known as FABP4), GLUT4, SCD, phosphenolpyruvate carboxykinase (PEPCK), and insulin receptors. As differentiation progresses the number of GLUT4 transporters and insulin receptors increases, as does insulin sensitivity, in order to promote lipid accumulation (Smas and Sul, 1995). Yamada et al. (2007) reported the protein expression of adipogenic transcription factors (C/EBPβ, C/EBPα, PPARγ) in different fat depots of Japanese Black Wagyu during the late feeding period at 19, 24, and 29 months of age. Expression of C/EBPβ- LAP decreased from 19-29 months of age, while C/EBPβ-LIP increased in the subcutaneous and intermuscular fat depots, indicating suppression of preadipocyte

13 differentiation during this period and advanced maturity in these fat depots. Expression of C/EBPα in intermuscular fat increased from 19-29 months of age, which correlated with the increase of triglyceride/DNA measured, indicating hypertrophy or lipid filling of adipocytes. No changes in C/EBPδ or PPARγ protein expression may represent the role of only maintaining expression of adipogenic, lipid metabolism, and glucose metabolism genes (Yamada et al., 2007). Pickworth et al. (2011) compared the expression of adipogenic genes in the subcutaneous and intramuscular fat depots in 13 month old high and low marbling SimAngus cattle. No significant differences were found between high and low marbling groups. However, expression of DLK-1 was greater in intramuscular fat, while LPL, PPARγ, FASN, and FABP4 were upregulated in the subcutaneous fat depot. To identify breed differences across time (19 vs 24 months of age), Yamada et al. (2009) compared adipogenic protein expression in different fat depots of Japanese Black Wagyu cattle with Holstein cattle. C/EBPβ-LAP and C/EBPα was upregulated in Wagyu when compared with Holstein cattle at 19 months of age only in the mesenteric fat depot. No breed differences were identified for C/EBPβ-LIP or PPARγ at either 19 or 24 months of age in any of the 3 fat depots. C/EBPδ was upregulated in Wagyu at 19 months of age in the subcutaneous, intermuscular, and mesenteric fat depots. Interestingly, plasma insulin concentrations tended to be greater in Wagyu cattle when compared with Holstein cattle at 19 months of age (Yamada et al., 2009). Insulin signaling activates PKB, which can phosphorylate Forkhead box protein O1 (FOXO1), and inhibit FOXO1 from traveling to the nucleus and inhibiting the transcription of other adipogenic genes (Farmer et al., 2006). Therefore, greater plasma insulin concentration may have been the reason for the greater expression of adipogenic proteins at 19 months of age instead of 24 months of age. Wang et al. (2009) measured the adipogenic gene expression in the muscle of Wagyu and Piedmontese sired cattle (1/2 Hereford) at 3, 7, 12, 20, 25, and 30 months of age. Preadipocyte gene markers, Pref-1 (DLK-1) and extracellular matrix protein, fibronectin, had significantly greater expression in Wagyu at 7 months of age, but then

14 dropped drastically. This significant upregulation of these genes may represent a period of preadipocyte proliferation, while the drop in expression was to allow for the progression of adipogenesis to occur. At 12 months of age C/EBPβ expression is increased in both breeds to signal the initiation of differentiation. The expression of PPARγ was relatively constant until 20 months of age when expression increased 6-7 fold in Wagyu cattle (Wang et al., 2009). Expression of other lipogenic genes (LPL, FASN, FABP4, SCD) followed a similar pattern to that of PPARγ, likely because PPARγ regulates their transcription. The following results may indicate an upregulation of proliferative and adipogenic genes in calves around 7-12 months of age, with extensive lipid filling of adipocytes occurring after 20 months of age. To further support this claim, expression of WNT10B was upregulated in Wagyu cattle at 12 months of age and decreased afterwards until 30 months of age, while secreted frizzled receptor protein 5 (SFRP5) had the inverse expression and peaked at 30 months of age. High expression of WNT10B inhibits differentiation, meaning preadipocytes could be in a proliferative stage, while high expression of SRFP5 blocks WNT signaling and allows for differentiation and lipid filling to occur (Mori et al., 2012). An interesting point to consider in this study was that weaned calves remained on pasture until entering the feedlot at 26 months of age. This management scheme is extremely different from the conventional scheme in the United States of sending weaned calves to the feedlot shortly after weaning and being ready for harvest between 12-16 months of age. Duarte et al. (2013) reported a greater amount of intramuscular fat along with greater expression of C/EBPα and PPARγ, but not C/EBPβ from the skeletal muscle of 24 month old Wagyu cattle when compared with Angus cattle. Wagyu cattle also had a greater density of cells that stained positive with FABP4, which was used as an indicator of adipocytes in the muscle tissue sections analyzed. Duarte et al. (2013) concluded the upregulation of adipogenic genes in Wagyu cattle were responsible for the greater number of adipocytes deposited within the skeletal muscle, which also contributed to a greater amount of intramuscular fat.

Effect of different cattle breeds on marbling ability and carcass value

Wagyu cattle

Wagyu cattle descended from Japan and are well known for their ability to produce highly marbled beef (Gotoh and Joo, 2016). Around 1900, crossbreeding became popular, but by 1910 these cattle were seen as inferior compared to their native Japanese cattle. As a result, the native Japanese cattle that were recognized as superior were extensively inbreed. Four distinct beef breeds are now recognized in Japan: Japanese Black cattle, Japanese Brown cattle, Japanese Shorthorn, and the Japanese Polled (Motoyama et al., 2016). Different prefectures in Japan selected for different economically important traits leading to the different variations within the breed. The most common breed, Japanese Black, has been selected for a superior ability to deposit marbling compared to other Japanese cattle breeds (Sasaki et al., 2006; Gotoh, 2014; Motoyama et al., 2016). Japanese Brown cattle, also known as “Akushi” were influenced by Simmental genetics, and deposit less marbling, but grow faster and have heavier carcass weights compared with Japanese Black cattle (Sasaki et al., 2006). The first Wagyu cattle came to the United States in 1976 and more in the early 1990’s (Lunt et al., 1993). Increased research has involved the use of Wagyu cattle due to their superior ability to marble compared with other cattle breeds. Radunz et al. (2009) reported that Black Wagyu sired cattle had a greater percentage of IMF at both the 12th and 6th rib (12.9 and 15.1%, respectively) when compared with Angus sired cattle (10.5 and 11.9 %, respectively) when both were raised to an average body weight of 544 kg. Lunt et al. (2005) compared the carcass quality of Angus and Black Wagyu cattle offered either a concentrate-based or hay diet to U.S. (8 months for concentrate, 12 months for hay) or Japanese endpoints (16 months for concentrate, 20 months for hay) and found a breed × endpoint interaction for lipid percentage in the longissimus thoracis. When cattle were taken to U.S. endpoints, Angus cattle deposited more IMF compared with Wagyu cattle when fed the concentrate-based diet (9.3 vs. 6.1%, respectively), but remained similar when fed the hay diet (8.3 vs. 7.8%, respectively). When cattle were taken to Japanese endpoints, Angus deposited similar amounts of IMF compared with Wagyu cattle when 16 fed the concentrate-based diet (14.7 vs. 14.1%, respectively), but less IMF when fed the hay diet (12.0 vs. 20.4%, respectively). Based on the study conducted by Lunt et al. (2005), it appears that additional time, either days on feed or older age, and dietary energy source may affect the deposition of IMF in Wagyu cattle. Subcutaneous fat from Wagyu cattle in this experiment tended to have lower levels of saturated fatty acids due to less C14:0, and C16:0, tended to have more mono-unsaturated fatty acids due to more C18:1n-9, and had more poly-unsaturated fatty acids due to more C18:2n-6, C18:3n-3, and C18:2t10,c12 when compared with fat from Angus cattle (Chung et al., 2006). Results from Chung et al. (2006) have demonstrated that Wagyu cattle more healthy fatty acids compared with Angus cattle. While it has been accepted that Wagyu have the ability to deposit extreme amounts of IMF when compared with other breeds of cattle, the mechanism to explain these differences has yet to be determined.

Angus and SimAngus cattle

Angus cattle are the most popularly used breed of beef cattle in the United States. Angus cattle are a British breed of cattle that matures quickly and has a moderate mature frame size. As a result, Angus cattle grow quickly and easily deposit fat. A reason Angus cattle are so popular in the United States is because of their ability to deposit more marbling when compared with other British and Continental breeds of cattle. However, Angus cattle can easily deposit excessive amounts of subcutaneous fat that can negatively affect YG and carcass value. SimAngus cattle are a British × Continental crossbred breed between Angus and Simmental cattle. Simmental cattle are a continental breed with a large mature frame, heavy muscling, and a fast rate of body weight gain. Simmental cattle carcasses have heavier hot carcass weights, greater muscling, and lower amounts of fat (subcutaneous and intramuscular) when compared with Angus cattle. While adding hybrid vigor, SimAngus cattle combine Angus and Simmental characteristics to produce a breed that is popular today among commercial cattlemen in the United States. Retallick et al. (2013) compared the effect of breed (Angus and Simmental) and heterosis of crossbred SimAngus cattle for feedlot performance and carcass 17 characteristics. Direct and Maternal Simmental breed influence resulted in greater initial, final, and carcass weights. Direct breed effects of Simmental resulted in the most desirable residual feed intake, greatest longissimus muscle area, hot carcass weight, and most desirable YG. Direct breed effects of Angus resulted in greater levels of backfat and greater marbling scores. The effect of heterosis improved gain to feed ratios, residual intake, and residual body weight.

Jersey cattle

Jersey cattle make up a small proportion of cattle used in the dairy industry in the United States compared with Holstein cattle. It is estimated that dairy cattle contribute to nearly 25% of the beef produced in the United States. In the 2016 National Beef Quality Audit dairy type cattle contributed 16.3% to the fed cattle surveyed (Boykin et al., 2017). However, the majority of these cattle are likely Holstein cattle, but the incorporation of Jersey genetics in the U.S. continues to increase as shown by the increasing sales of Jersey semen. There has been a 10.85% increase from 2012 to 2013 to a total of 2,747,482 units compared to 2003 when only 1,071,651 units were sold domestically in the U.S. (NAAB). An industry problem has been that Jersey bull calves demand very little, if any economic return for Jersey dairy producers. Dal Zotto et al. (2009) reported that purebred dairy bull calves had a lower value (-$28.76/calf and -$20.70/calf for Brown Swiss and Holstein Fresian, respectively) when compared with female counterparts that could be used as replacements within the dairy herd. However, with crossbreeding, male calves were valued +$77.56 to +$141.58 more than female counterparts (Dal Zotto et al., 2009). Dal Zotto et al. (2009) demonstrated that with the use of a terminal sire, in this case Limousin and Belian Blue bulls, crossbred calves brought a greater price (+$2.65 ± 0.03/kg) and market value (+$192.98 ± 2.04/calf) compared to purebred calves. Therefore, there may be an incentive to crossbreed Jersey cows with a terminal sire, which would increase the influence of Jersey genetics in the fed cattle population in the United States. Jersey cattle are well known for their small frame and dairy producing ability. Interestingly, not many are aware of the marbling ability of dairy cattle, particularly 18

Jersey and Holstein cattle, which on average receive small or modest marbling scores (Lehmkuler and Ramos, 2008; Arnett et al., 2012). However, Jersey cattle perform poorly in the feedlot compared with beef cattle breeds. Jersey cattle are slow growing and require a long period of time on feed to reach a body weight that will produce an adequately sized beef carcass (Cole et al., 1964; Pitchford et al., 2002; Barton and Pleasants, 1997; Lehmkuler and Ramos, 2008; Arnett et al., 2012; Jiang et al., 2013). Packers in the United States are becoming more acceptable of heavier carcass weights, but discount heavily for light weight carcasses, such that on February 27, 2018 the discount for carcasses between 500 and 600 pounds was -$14.97 (USDA, 2018). Purebred Jersey cattle may not be economical for beef production due to these reasons; however, Jersey cattle may be able to create a high value beef carcass with the use of crossbreeding with a terminal sire.

Chapter 3. Evaluation of Feedlot Performance, Carcass Characteristics, Carcass Retail Cut Distribution, Warner-Bratzler Shear Force, and Fatty Acid Composition of Purebred Jersey and Crossbred Jersey Steers

ABSTRACT

Feedlot performance, carcass yield, fatty acid composition, and tenderness of crossbred Jersey steers compared with purebred Jersey steers was investigated. Purebred Jersey (n=21) and crossbred Jersey steers sired by Angus (n=9), SimAngus (n=10), and Red Wagyu (n=15) bulls were assessed. Adjusted to a common initial body weight (BW), crossbred Jersey steers had a greater rate of BW gain (P ≤ 0.01) compared to purebred Jersey steers. Angus sired steers had a greater daily dry matter intake (P ≤ 0.01) compared to Wagyu and Jersey sired steers, whereas SimAngus sired steers had a greater daily dry matter intake compared to Jersey sired steers. Wagyu sired steers were more feed efficient (P ≤ 0.03) compared to Jersey sired steers. Even with a greater (P ≤ 0.01) number of days on feed, off-test BW of purebred Jersey steers was less (P ≤ 0.01) compared to crossbred Jersey steers. Adjusted to a common hot carcass weight, Angus sired steers had a greater backfat thickness (P ≤ 0.01) compared to steers from the other sire breeds. Kidney fat percentage (P ≤ 0.01) was greatest for Jersey sired steers, with SimAngus and Wagyu sired steers being intermediate, and the lowest for Angus sired steers. Carcasses from Angus and Wagyu sired steers had a greater marbling score (P ≤ 0.03) compared to carcasses from Jersey sired steers. Carcasses from Wagyu sired steers had a greater (P ≤ 0.01) total red meat yield compared to Angus and Jersey sired steers, whereas SimAngus sired steers had a greater total red meat yield compared to Jersey sired steers. Carcasses from Angus sired steers tended (P = 0.07) to have a greater percentage of fat trim compared to Wagyu sired steer carcasses. There were no sire breed differences (P = 0.38) for the percentage of total bone from the carcasses. Tenderness,

20 measured by Warner-Bratzler shear force (WBSF), was improved (P ≤ 0.01) with 14 days of postmortem aging compared to 7 days. Wagyu and SimAngus sired steers produced steaks with a lesser (P ≤ 0.01) WBSF compared to steaks from Angus and Jersey sired steers. Steaks from Angus sired steers tended (P = 0.10) to have a greater percentage of total lipid and had a greater (P ≤ 0.05) percentage of 16:0 compared to steaks from Jersey sired steers. Overall, crossbred Jersey steers improved economically relevant production parameters of feedlot performance, carcass quality, carcass yield, and instrumental predictors of eating quality compared to purebred Jersey steers.

INTRODUCTION

Jersey cattle are a dairy breed and are not typically thought of contributing to the fed beef supply. However, Jersey bull calves are a by-product of the dairy industry and contribute to the fed beef supply. The incorporation of Jersey genetics continues to increase in the United States dairy industry as shown by a 10.85% increase in domestic semen sales from 2012 to 2013 and a 7.75% increase from 2013 to 2014 (NAAB, 2015). According to the 2016 National Beef Quality Audit, dairy type cattle accounted for 16.3% of the fed cattle harvested (Boykin et al., 2017). Therefore, as the influence of Jersey genetics increases, there are likely to be more Jersey influenced steer calves available to be raised for beef production in the future. Jersey cattle are smaller framed, slower growing, and finely muscled compared to other breeds of cattle, especially beef cattle breeds (Cole et al., 1964; Koch et al., 1976). As a result, the sale of purebred Jersey male calves provides very little economic return to Jersey dairy producers due to the anticipated poor growth and projected light finishing weights of purebred Jersey steers in the feedlot. In addition, fattened purebred Jersey steers also receive dairy-type discounts for light muscling when sold to the packing plant. These negative economic factors have resulted in little to no demand for purebred Jersey steers in the U.S. commercial beef industry. However, Jersey cattle can produce high quality beef with a superior eating satisfaction. Purebred Jersey cattle can deposit sufficient amounts of marbling to receive Low to Average Choice USDA Quality grades 21

(Lehmkuhler and Ramos, 2008; Arnett et al., 2012). Cole et al. (1964) reported similar marbling scores between Jersey steers and British (Angus and Hereford) steers. Subsequently, Jersey steers were reported to have the greatest tenderness, flavor, and juiciness scores for loin and round steaks compared to other breeds of cattle (Hereford, Angus, Brahman, Brahman cross, Santa Gertrudis, Holstein, and Charolais cross) when assessed by both a laboratory and family panel (Cole et al., 1964; Ramsey et al., 1963). A trained sensory panel described by Arnett et al. (2012) reported greater tenderness, juiciness, beef flavor intensity, and overall acceptability scores for strip steaks from Jersey steers offered a high concentrate diet compared to commodity derived strip steaks that represented commodity boxed beef sold in the U.S. Therefore, Jersey beef may be more suitable for niche markets or value-added markets, such as white tablecloth restaurants and certain export markets that demand high quality beef products with superior eating satisfaction. Niche markets commonly establish well defined labeling criteria that have a real or perceived positive effect on characteristics related to eating quality, sustainability, management or raising practices, human health benefits, and other attributes desired by the consumer. This present study was designed to investigate the implementation of a crossbreeding program between Jersey cows and a terminal beef sire for the production of a high quality beef product to be sold into value added markets targeting the use of no exogenous growth promoting technologies (e.g. hormone implants and β-agonists), and to improve the value of male calves from Jersey herds through improved feedlot performance, carcass yield, and beef quality. We hypothesized the production of terminally sired crossbred Jersey calves, when compared to purebred Jersey calves, would result in improvements for economically relevant measures related to feedlot performance, carcass yield, and beef eating quality. The objectives of this study were to evaluate economically relevant measures related to the feedlot [average daily gain (ADG) and feed efficiency], carcass composition (muscle, fat, and bone yields), carcass quality (marbling and fatty acid composition), and beef tenderness [Warner-Bratzler shear force

(WBSF)], with the overarching goal to assess their potential use in labeling claims to add value to products from Jersey influenced cattle.

MATERIALS AND METHODS

Animal procedures and husbandry practices were approved by the Institutional Animal Care and Use Committee (IACUC; protocol number 2015A00000093) of The Ohio State University and followed the guidelines recommended in the Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching (FASS, 2010). Animals and treatments

Purebred Jersey and crossbred Jersey steer calves were used in the present study. Purebred Jersey steers were sired by 11+ sires, while crossbred Jersey steer calves were produced by terminal sires from three breeds, Angus (n = 1 sire), SimAngus (n = 2 sires), and Red Wagyu (n = 3 sires); bulls within a terminal sire breed were selected for calving ease and marbling ability. The study was conducted as a randomized complete block design over the course of 2 years (2015 and 2016), with year used as the block. Steer calves arrived at the Ohio Agricultural Research and Development Center (OARDC) feedlot with an average initial body weight (BW) of 210 ± 31 kg and an age of 237 ± 31 d with a sire breed occurrence of: Jersey (n = 21), Angus (n = 9), SimAngus (n = 10), and Red Wagyu (n = 15). The day after arrival, steer calves were weighed, ear-tagged, and vaccinated before being separated into individual pens. Each pen (2.6 × 1.5 m) consisted of concrete slatted floors, with a 1.5 m long concrete feed bunk, and supplied ad libitum access to clean fresh water. Feeding and management

23 diet by substituting 10% of the corn silage for whole shelled corn. The first finishing diet containing corn silage was offered for approximately 100 d. The switch to the second finishing diet, which replaced corn silage with soy hulls, occurred over one day and was offered for the remainder of the feeding period. Feed allocation and feed refusals were weighed daily prior to feeding at 0930 to record individual feed intake. Feed samples were collected and saved every week to determine dry matter (DM) percentage (AOAC, 1984) and a composite sample of each dietary ingredient was analyzed for nutrient composition (Rock River Laboratory Inc., Wooster, OH). Initial BW was measured the day after arrival to the OARDC feedlot, but before feeding for the day. Interim BW measurements were taken prior to feeding every 28 d to monitor BW gain and calf health. The targeted endpoint for steers was a live BW of 523 kg. Steers were removed in groups of 6 to 8 for harvest at 14 d intervals as target endpoints were reached. Due to the duration of time on feed needed for cattle to reach the predetermined harvest endpoint, some cattle (primarily purebred Jersey and Wagyu crossbreds) had to be removed and harvested prior to reaching the target BW to provide feedlot pens for cattle the subsequent year. Off-test BW was recorded just prior to removal of the cattle from the feedlot. Carcass fabrication

Cattle were transported 160 km for harvest at The Ohio State University abattoir in Columbus, Ohio. The following day cattle were harvested and final BW and hot carcass weight (HCW) were recorded. After carcasses chilled for 7 days at 4 ºC, chilled carcass weight was recorded and carcasses were split between the 12th and 13th ribs to determine backfat thickness (BFT), longissimus muscle area (LMA), carcass maturity, marbling score, USDA quality grade (QG), USDA yield grade (YG), and percent boneless closely trimmed retail cuts (BCTRC). CIELAB color (L*, a*, and b*) was measured with a Konica Minolta colorimeter CR-410 (Minolta Company, Ramsey, NJ), with a 50 mm diameter aperture and D65 illuminant calibrated against a white tile, on the longissimus muscle at the 12th rib and subcutaneous fat over the 11th and 12th ribs.

Carcass kidney fat (KF) percentage was determined by the removal and weighing of the kidney fat during the fabrication process, divided by the chilled carcass weight. The right side of each carcass was fabricated into primal and sub-primal beef cuts according to USDA Agricultural Marketing Service’s (AMS) Institutional Meat Purchase Specifications (IMPS) to determine carcass cut-out yield and distribution (USDA, 2014). The following primal and sub-primal weights were recorded: 112A ribeye roll, 124 back ribs, 114 shoulder clod, 114D top blade, clod teres major, 116A chuck roll, 116B chuck tender, 120 brisket, inside and outside skirt steak, 167A knuckle, 168 top/inside round, 171B bottom round, 171C eye of round, 174 short loin, 180 strip loin, 184 top sirloin butt, 184D top sirloin butt cap, 185B ball tip, 185D tri-tip, 191A butt tender, 192A tenderloin tail, 193 flank steak, 80:20 lean trim, fat trim, and bone weight. Warner-Bratzler shear force

Four 2.54 cm thick steaks were cut from the posterior end of the ribeye roll and randomized to a postmortem aging period of either 7, 14, 21, or 28 days at 4 ºC, and subsequently frozen at -20 ºC. Prior to cooking, steaks were thawed over night at 4 ºC. Cooking and WBSF were conducted according to guidelines set by the American Meat Science Association (AMSA, 2015). Cooking temperature was monitored using a thermocouple probe (5.08 cm Mini Needle Probe) and a thermocouple reader (ThermaData Thermocouple Logger KTC). Steaks were cooked on a flat top grill set at 190 ºC, flipped at an internal temperature of 40 ºC, and removed at an internal temperature of 71 ºC. Steaks were allowed to cool over night at 4 ºC. The next day, six round cores (1.27 cm diameter) were collected parallel to the muscle fibers from each steak. Cores were sheared perpendicular to the muscle fibers with a WBS v-notch blade using a TA.XT2 plus texture analyzer (Texture Technologies Corp., Scarsdale, New York). The crosshead speed was set at 200 mm/min and the peak force required to shear the sample was recorded. Longissimus fatty acid composition

Fatty acid extraction and methylation procedures used were from Folch et al. (1957) and Doreau et al. (2007), respectively. A thin slice of the longissimus muscle 25

(~20 g), free of subcutaneous fat and connective tissue, was collected and frozen on d 7 from the ribeye roll for fatty acid composition analysis. Longissimus muscle samples were each ground in a blender to create a homogenous sample, from which 1 g of ground tissue was added to a pyrex tube containing a screw cap. In addition to the ground tissue, 2 ml of an internal standard (0.5 mg 19:0/ml; Nu-Chek Prep, Inc. Elysian, MN), 0.7 ml of 10N KOH in water, and 4.3 ml of methanol were added and vortexed for 120 s. Next, sample tubes were placed in a 55 ºC hot water bath for 90 min, with 5 s of rigorous shaking taking place every 20 min for each sample. Samples tubes were placed in an ice water bath to cool samples to room temperature before adding 0.58 ml of 24N H2SO4 to each sample tube. Sample tubes were mixed by inversion and placed back in the 55 ºC hot water bath for 90 min, with 5 s of rigorous shaking taking place every 20 min for each sample once again. Afterwards, sample tubes were cooled again in an ice water bath before the addition of 3 ml of hexane. Sample tubes were vortexed and centrifuged for 5 min. each and then the hexane layer was extracted and placed in a gas chromatography vial to be analyzed. All fatty acid methyl esters were separated by gas- liquid chromatography using a CP-SIL88 capillary column (100 m x 0.25 mm x 0.2-μm film thickness). The indices of delta desaturation enzyme activity on the conversion of 14:0 to 14:1, 16:0 to 16:1, and 18:0 to 18:1 cis 9 were calculated as follows: [e.g. = 100 × (18:1 cis 9 / (18:0 + 18:1 cis 9))]. Statistical Analysis

Statistical analyses were performed using the PROC MIXED procedure in SAS and the PROC GLIMMIX procedure for determining the distribution of USDA QG (SAS Inst. Inc., Cary, NC). The experimental design was a randomized complete block design with steer as the experimental unit. The statistical model used was: Yij = μ + Bi + yj + eij, where Bi = sire breed as a fixed effect, and the random effect of yj = year, and eij = random error. The statistical model used for WBSF was: Yijkl = μ + Bi + Pj + BPij + yk + al + eijkl, where Pj = postmortem aging and BPij = sire breed × postmortem aging as fixed effects, and the random effect of al = animal. The LSMEANS and PDIFF statements were used to record treatment least square mean estimates, standard errors, and

26 distinguish differences between the treatment levels. When significant, initial BW, HCW, and chilled side weight were used as covariates for the feedlot performance data, carcass data, and cut-out data, respectively. A significance of fixed effects and covariates was established at P ≤ 0.05 and tendencies are discussed at 0.05 < P ≤ 0.10.

RESULTS AND DISCUSSION

Feedlot Performance

Prior to adjustment, Angus and Jersey sired steer calves (222 and 225 kg, respectively) had a greater (P ≤ 0.01) initial BW (SD = 31.4 kg) compared to SimAngus and Wagyu sired steer calves (198 and 194 kg, respectively). Therefore, the feedlot performance measures for steers were adjusted to a similar initial BW (210 kg; Table 2) using a linear covariate. The adjusted receiving age of purebred Jersey steer calves was greater (P ≤ 0.01) compared to the receiving age of crossbred steer calves at the initiation of the present study. Over the course of the feeding trial, the ADG of crossbred Jersey steers was greater (P ≤ 0.01) compared to purebred Jersey steers, and SimAngus sired steers tended to have a greater (P = 0.06) ADG compared to Wagyu sired steers. Angus sired steers had a greater average daily dry matter intake (DMI; P ≤ 0.01) compared to Wagyu and Jersey sired steers, while SimAngus sired steers had a greater (P ≤ 0.03) average daily DMI compared to Jersey sired steers and tended to have a greater (P = 0.08) average daily DMI compared to Wagyu sired steers. Wagyu sired steers were more feed efficient (P ≤ 0.01), and SimAngus sired steers tended (P = 0.09) to be more feed efficient, compared to Jersey sired steers. Purebred Jersey steers required more (P ≤ 0.01) days on feed compared to crossbred Jersey steers, and Wagyu sired steer required more days on feed (P ≤ 0.02) compared to Angus sired steers, before being removed from the feeding trial for harvest. As a result of both a greater age at feedlot entry and number of days spent on feed, purebred Jersey steers were older (P ≤ 0.01) compared to crossbred Jersey steers at the time of harvest, while Wagyu sired steers tended (P = 0.09) to be older than Angus sired steers. Even with a greater number of days spent on feed by purebred Jersey 27 steers compared to crossbred Jersey steers, facility constraints required purebred Jersey steers to be removed before reaching the targeted BW endpoint, resulting in greater (P ≤ 0.01) off-test BW for crossbred Jersey steers compared to purebred Jersey steers. A lesser ADG from Jersey cattle or Jersey sired cattle compared to other breeds of cattle offered concentrate based diets has been commonly reported (Cole et al., 1964; Smith et al., 1976; Young et al., 1978; Lehmukuler and Ramos, 2008). Jersey sired steers have been reported to consume less feed and be less feed efficient compared to other breeds of cattle, including Simmental and Angus sired steers from Hereford or Angus cows (Smith et al., 1976). Retallick et al. (2013) compared Angus, Simmental, and SimAngus crossbred steers and found no difference in DMI of steers, but the influence of Simmental genetics tended to increase ADG and improve feed efficiency compared to the influence of Angus genetics. Smith et al. (1976) also reported a greater ADG of steers from Simmental sires compared to Angus sires. Similar feedlot performance results between Angus and SimAngus sired steers in the present study may be the result of random sire sampling within and across breeds, as no attempt was made to identify bulls reflective of sire breed averages. Radunz et al. (2009) compared Angus and Black Wagyu sired cattle from Angus cows and reported a greater ADG and DMI from Angus sired cattle compared to Wagyu sired cattle; however, Wagyu sired cattle were more feed efficient compared to Angus sired cattle. The results of the present study for ADG and feed efficiency numerically follow the same trend as reported by Radunz et al. (2009). However, the results of the present study are not in agreement with significant differences for ADG and feed efficiency between Angus and Wagyu sired cattle. Additionally, in contrast to Radunz et al. (2009), Red Wagyu or “Akaushi” sires from the Kumamoto lineage were used in the present study rather than Black Wagyu sires from the Tajima lineage. Black Wagyu cattle typically have a slower rate of gain, but deposit more marbling when compared to Red Wagyu cattle (Sasaki et al. 2006; Motoyama et al., 2016), which may contribute to the observed differences between studies.

Carcass Characteristics

Carcass characteristics from purebred and crossbred Jersey steers were adjusted to a similar HCW (319 kg) to compare carcass measures consistently across sire breeds (Table 3). Final live BW prior to harvest was not different (P = 0.36) between steers; however, crossbred Jersey steers had a greater (P ≤ 0.01) dressing percentage compared to purebred Jersey steers. Prior to adjustment, Angus and SimAngus sired steers (334 and 332 kg, respectively) had a greater (P ≤ 0.01) HCW (SD = 29.6 kg) compared to Wagyu and Jersey sired steers (317 and 304 kg, respectively). Angus sired steers produced carcasses with a greater (P ≤ 0.01) BFT compared to carcasses from SimAngus, Wagyu, and Jersey sired steers. Longissimus muscle area (LMA) was not different (P = 0.12) between carcasses from the different sire breeds. However, the LMA:HCW ratio tended (P = 0.09) to be affected by sire breed, with Wagyu sired carcasses having a greater LMA:HCW ratio compared to Jersey sired carcasses. Jersey sired steers had the greatest (P ≤ 0.01) KF percentage (7.9%), followed by Wagyu and SimAngus sired steers (6.4%), and lastly Angus sired steers (5.3%). There were no differences in calculated USDA YG (P = 0.16) and calculated percent BCTRC (P = 0.16) for carcasses from the different sire breeds. Carcass maturity scores were also similar (P = 0.25), as all carcasses were young cattle representing ‘A maturity’. Carcasses from Angus and Wagyu sired steers had a greater (P ≤ 0.03) marbling score compared to carcasses from Jersey sired steers. On average, Angus sired steers had a slightly abundant degree of marbling, Wagyu and SimAngus sired steers had a moderate degree of marbling, while Jersey sired steers had a modest degree of marbling. This resulted in carcasses from Angus sired steers receiving a significantly greater (P ≤ 0.04) USDA QG score compared to carcasses from Jersey sired steers. Average USDA QG was Low Prime for carcasses from Angus sired steers, High Choice for carcasses from Wagyu and SimAngus sired steers, and Average Choice for carcasses from Jersey sired steers. The distribution of USDA QG for steers in the present study is presented in Table 3. In accordance with the feedlot performance results reported in the present study, Jersey sired steer data are typically reported with a lesser HCW compared to other sire

29 breeds due to a lesser ADG and mature frame size when offered a concentrate based diet in a feedlot setting (Cole et al., 1964; Koch et al., 1976; Koch and Dikeman, 1977; Young et al., 1978; Lehmkuhler and Ramos, 2008). Purebred and Jersey sired steers typically have lesser dressing percentages (Cole et al., 1964; Koch et al., 1976; Koch and Dikeman, 1977; Lehmkuhler and Ramos, 2008) compared to steers from other sire breeds, which also contributes to their lesser HCW. The lesser dressing percentages for purebred Jersey steers could be due to a combination of factors, such as a lesser weight of muscle and the potential for loss of internal (kidney) fat weight during evisceration or final trimming relative to other breeds of cattle. Angus sired steers had the greatest BFT when compared to the other sire breeds in this study. This is in agreement with previous literature reports (Cole et al., 1964; Charles and Johnson, 1976; Kempster et al., 1976; Koch et al., 1976; Pitchford et al., 2002) that describe steers with Angus and Hereford genetics as having greater deposits of subcutaneous fat relative to other breeds of cattle. Radunz et al. (2009) reported a greater fat thickness at the 6th rib, but not at the 12th rib of carcasses from Angus sired cattle when compared to Wagyu sired cattle. Also in agreement with the results from the present study, Retallick et al. (2013) reported a greater BFT for Angus steers compared to Simmental and SimAngus steers. Interestingly, Jersey cattle appear to have a very different pattern of carcass fat distribution compared to Angus cattle. In the present study, Jersey sired steers had a lesser thickness of backfat and a greater percentage of kidney fat, while Angus sired steers had a greater thickness of backfat and a lesser percentage of kidney fat. Previous reports by Cole et al. (1964) and Koch et al. (1976) agree with a greater percentage of kidney fat in purebred Jersey and Jersey sired steer carcasses relative to other breeds of cattle. Kempster et al. (1976) also reported crossbred Angus steers to have a numerically lesser percentage of kidney fat relative to steers from 15 other breed × diet groups. Jersey sired steers have previously demonstrated their ability to deposit marbling at similar levels to cattle breeds, such as Angus and Wagyu, which are commonly known to produce highly marbled beef (Pitchford et al., 2002). Koch et al., (1976) reported that Jersey sired steers had a numerically greater percentage

30 of fat in the longissimus muscle (8.2%) compared to other sire breeds, such as Angus (7.6%) and Hereford (5.5%) adjusted to a similar HCW. Purebred Jersey steers have been reported to deposit small to modest amounts of marbling when finished on a high concentrate diet (Lehmkuhler and Ramos, 2008; Arnett et al., 2012). Results from the current study more closely align with the marbling scores reported more recently by Lehmkuhler and Ramos (2008) and Arnett et al. (2012), with purebred Jersey steer carcasses averaging a modest degree of marbling in the present study. In disagreement with some of the previous reports mentioned, purebred Jersey steers had a lesser marbling score compared to the other sire breeds used in the present study. Overall, there were significant differences in the distribution of fat on the carcasses from steers sired by the different breeds of cattle in the present study. Purebred Jersey steers had similar LMA compared to the crossbred Jersey steers sired by the beef breeds investigated. Lehmkuhler and Ramos (2008) reported smaller LMA from purebred Jersey steers when compared to Holstein steers; however, purebred Jersey steers had a greater LMA:HCW ratio compared to Holstein steers. In agreement with the expectation that Jersey cattle are lighter muscled than other breeds of cattle, Cole et al. (1964) reported that Jersey steers had a lesser LMA and round circumference compared to beef breeds of cattle. Koch et al. (1976) and Young et al. (1978) reported that Jersey sired steers had lesser LMA compared to South Devon, Simmental, Limousin, and Charolais sired crossbred steers. Radunz et al. (2009) reported that there was a tendency for Wagyu sired cattle to have greater LMA compared to Angus sired cattle. Retallick et al. (2013) reported SimAngus steers to have greater LMA compared to Angus steers due to the influence of Simmental genetics. The lack of significant sire breed differences for the LMA in the present study may reflect the randomness of sire sampling within and across the sire breeds evaluated, but may also be due to the large amount of variation in the LMA from steers in the present study (SD = 8.71 cm2). Lean color of the longissimus muscle was lighter (greater L* value; P ≤ 0.01) for Angus sired steers, followed by Wagyu and SimAngus sired steers, and lastly Jersey sired steers had the darkest colored lean. Lean lightness (L*) values followed a similar pattern

31 as marbling score, with carcasses from Angus sired cattle having a greater CIELAB L* value, carcasses from SimAngus and Wagyu sired cattle being intermediate, and Jersey sired steer carcasses having the lowest CIELAB L* value. There was a significant (P ≤ 0.01; r = 0.52) positive correlation between lean CIELAB L* and marbling, demonstrating lean color lightness is influenced by the degree of marbling present within the muscle. Wulf et al. (1999) also reported a weaker (r = 0.26), but significant correlation between lean CIELAB L* values and marbling score. SimAngus sired steers had a redder (greater a* value; P ≤ 0.01) colored lean compared to Angus and Jersey sired steers, while Wagyu sired steers had a redder colored lean compared to Jersey sired steers. There were no sire breed differences for lean CIELAB b* values (P = 0.12), fat CIELAB L* values (P = 0.29), and fat CIELAB a* values (P = 0.36). Dairy cattle have previously been reported to have lesser colorimeter values (L*, a*, b*) when compared with native Bos Taurus and Bos Indicus cattle (Page et al., 2001), which is in agreement with the findings in the present study. Interestingly, Angus sired steers produced carcasses with a more yellow (greater b* value; P ≤ 0.01) carcass fat when compared to carcasses from SimAngus, Wagyu, and Jersey sired steers. Jersey cattle are a breed of cattle commonly known to produce yellow carcass fat due to the greater concentrations of β-carotene in their fat (Kruk, et al., 1998). Tian et al. (2010) reported Jersey cattle have a higher frequency of the AA genotype for the β-carotene-9, 10-dioxygenase (BCO2) gene, which leads to the loss of enzyme function and a greater accumulation of β-carotene in the carcass fat that results in the yellow fat color. Therefore, Angus sired steers in the present study may have had greater concentrations of β-carotene deposited in their carcass fat relative to steers from the other sire breeds due to their BCO2 allele frequency. Carcass Cut-Out Distribution

The effect of sire breed on the carcass cut-out distribution comparing purebred Jersey steers and crossbred Jersey steers is compared at a similar chilled side weight (155 kg; Table 4). Prior to adjustment, Angus and SimAngus sired steers (162 and 161 kg, respectively) had a greater (P ≤ 0.01) chilled side weight (SD = 14.1 kg) compared to

Wagyu and Jersey sired steers (154 and 148 kg, respectively). SimAngus and Wagyu sired steer carcasses had a greater (P ≤ 0.02) weight of total red meat (retail cuts and lean trim) compared to Jersey sired steer carcasses, while Wagyu sired steer carcasses tended (P = 0.07) to have a greater weight of total red meat compared to Angus sired steer carcasses. Wagyu sired steer carcasses had a greater retail yield (P ≤ 0.01) and total red meat yield (P ≤ 0.01) compared to Angus and Jersey sired steer carcasses, while SimAngus sired steer carcasses had a greater retail yield (P ≤ 0.01) and total red meat yield (P ≤ 0.03) compared to Jersey sired steer carcasses. There were no differences in bone yield (P = 0.37); however, carcasses from Angus and Jersey sired steers tended (P = 0.07) to have a greater fat yield compared to carcasses from Wagyu sired steers. SimAngus sired steer carcasses had a greater (P ≤ 0.05) weight of retail cuts in the chuck compared to Jersey sired steer carcasses, which was the primary result of a greater (P ≤ 0.02) shoulder clod weight and the accumulation of small, non-significant increased weights of other muscles in the chuck for SimAngus sired steer carcasses relative to Jersey sired steer carcasses. Wagyu sired steer carcasses tended to have a greater weight of retail cuts in the chuck (P = 0.06) and greater clod weight (P = 0.07) compared to Jersey sired steer carcasses. Angus sired steer carcasses had a greater (P ≤ 0.01) weight of brisket contributing to their carcass weight compared to carcasses from the other sire breeds. There was no difference (P = 0.81) in the weight of retail cuts in the rib primal between carcasses from the different sire breeds. Wagyu sired steer carcasses had a greater (P ≤ 0.01) weight of retail cuts in the loin primal when compared to carcasses from the other sire breeds. Greater loin primal weight was influenced by Wagyu sired steer carcasses having a greater weight from the striploin (P ≤ 0.01) and bottom sirloin tri-tip (P ≤ 0.03) compared to the other sire breeds and a greater weight from the short loin (P ≤ 0.01) and top sirloin butt (P ≤ 0.01), compared to Angus and Jersey sired steer carcasses. SimAngus sired steer carcasses tended (P = 0.06) to have a greater short loin weight compared to Jersey sired steer carcasses. Wagyu and SimAngus sired steer carcasses had a greater top sirloin butt cap (P ≤ 0.04) weight compared to Angus and Jersey sired steer carcasses. There were no sire breed differences (P = 0.21) in the weight

33 of the flank steak; however, for SimAngus sired steer carcasses, the outside skirt steak had a greater (P ≤ 0.03) weight compared to the other sire breeds. In the round primal, Wagyu sired steer carcasses had a greater (P ≤ 0.01) weight of retail cuts in the round compared to Jersey and Angus sired steer carcasses and tended (P = 0.08) to have a greater weight of retail cuts in the round compared to SimAngus sired steer carcasses. SimAngus sired steer carcasses had a greater (P ≤ 0.01) weight of retail cuts in the round compared to Angus sired steer carcasses, while Jersey sired steer carcasses tended (P = 0.06) to have a greater weight of retail cuts in the round compared to Angus sired steer carcasses. Wagyu sired steer carcasses had a greater weight for the top round (P ≤ 0.01) and bottom round flat (P ≤ 0.01) compared to the other sire breeds, whereas, SimAngus sired steer carcasses tended (P = 0.06) to have a greater weight for the top round compared to Angus sired steer carcasses. SimAngus sired steer carcasses had a greater (P ≤ 0.02) weight for the bottom eye of round compared to Angus and Jersey sired steer carcasses and tended (P = 0.10) to have a greater weight for the bottom eye of round compared to Wagyu sired steer carcasses. There was no difference in the weight of total lean trim (P = 0.42) and total bone (P = 0.57) between carcasses from the different sire breeds. However, carcasses from crossbred Jersey steers had a greater (P ≤ 0.05) weight of lean trim from the hind quarter compared to purebred Jersey steer carcasses. Angus sired steer carcasses had the greatest (P ≤ 0.02) weight of trimmed fat from the front quarter, while Jersey sired steer carcasses had the greatest (P ≤ 0.03) weight of trimmed fat from the hind quarter due to a greater (P ≤ 0.01) weight of kidney fat compared to carcasses from the other sire breeds. As a result, total fat trim was greater (P ≤ 0.04) for Angus and Jersey sired steer carcasses compared to Wagyu sired steer carcasses. Koch and Dikeman (1977) reported the carcass cut-out composition of implanted steers sired by Hereford, Angus, Jersey, South Devon, Limousin, Charolais, and Simmental bulls mated to Hereford and Angus cows with a similar days on feed endpoint. Koch and Dikeman (1977) reported a similar carcass cut-out percentage between crossbred Angus and Jersey sired steers for the chuck (19.6%), rib (6.2%), loin (9.7%), and round (16.3% and 15.5%) primals; however, these percentages were less

34 when compared to Simmental sired steers (21.0%, 6.4%, 10.3%, and 18.1%, respectively). Crossbred Simmental and Angus sired steers had greater percentages of retail product from the brisket (2.7%) compared to crossbred Jersey sired steers (2.4%). Overall, Koch and Dikeman (1977) reported greater retail yield from steers with Continental sire influence (Simmental, 68.9%) compared to British sire influence (Angus, 64.4% and Jersey, 63.4%), while the fat trim yield was greater from Angus and Jersey sired steers (24.5%) compared to Simmental sired steers (18.1%), with all steers having a relatively similar percentage of total bone yield (11.3 to 12.9%). Results of the present study are in agreement with the results of Koch and Dikeman (1977) for the percentage of retail product in the chuck, brisket, rib, loin, and round between Angus and Jersey sired steers. However, cut-out data from the SimAngus sired steers in the present study did not match the retail cut percentages reported for Simmental steers from the Koch and Dikeman (1977) study. The lack of differences observed between SimAngus sired steers in our study versus the large differences observed from Simmental sired steers in the Koch and Dikeman (1977) study may be due to the influence of Angus genetics in the SimAngus cross. Overall, the distribution of retail products across sire breeds in the present study differed much less than the sire breed effects reported by Koch and Dikeman (1977); however, crossbreeding appeared to improve carcass cut-out composition when compared to purebred Jersey steers. Comparing the cutability and carcass cut-out distribution of Wagyu sired steers to previous literature is difficult due to a limited number of literature reports, which is partially due to the Wagyu breed being relatively new to the United States and because carcass retail yield is more likely to be estimated from established predictor equations to save time and money. However, Greenwood et al. (2006) previously reported retail yield comparisons between Wagyu and Piedmontese sired steers and heifers from Hereford cows. Wagyu and Piedmontese sires reported by Greenwood et al. (2006) were selected based on a combination of muscling and marbling, with no mention of Myostatin genotype for the Piedmontese sires used. Wagyu sired cattle produced carcasses with a lesser HCW, dressing percentage, and LMA, but Wagyu sired cattle had a greater BFT

35 and marbling score when compared with Piedmontese sired cattle (Greenwood et al., 2006). Wagyu sired cattle also produced a lesser carcass retail yield, with a similar bone yield, and greater fat trim yield when compared to Piedmontese sired cattle (Greenwood et al., 2006). Wheeler et al. (2004) reported estimates for retail yield, fat yield, and bone yield of implanted steers sired by Hereford, Angus, Norwegian Red, Swedish Red and White, Holstein, and Wagyu bulls mated to Hereford, Angus, and MarcIII cows at different adjusted endpoints (age, HCW, BFT, marbling, percent fat trim). At a similar hot carcass weight (356 kg), Wagyu sired steer carcasses had a similar weight of retail product, fat, and bone compared to Angus sired steer carcasses. Results from the present study agree with those of Wheeler et al. (2004) that Wagyu sired steer carcasses have a similar bone yield compared to Angus sired steer carcasses. However, we noticed a tendency for Wagyu sired steer carcasses to have a lesser fat yield and a greater retail yield when compared to Angus sired steer carcasses. Based upon the results of the present study and the reviewed literature, Angus and Jersey sired steers are expected to have a similar retail yield and fat yield, with Jersey sired cattle having a slightly greater bone yield. SimAngus and Wagyu sired steers are expected to have a greater retail yield, lesser fat yield, and similar bone yield compared to Jersey sired steers. Review of the literature indicates sire breeds with more continental influence, such as Simmental, Charolais, Limousin, and Piedmontese, may have an even greater retail yield, lesser fat yield, and similar bone yield compared to SimAngus and Wagyu sired steers. Overall, and similar to findings reported by Mukhoty and Berg (1971) and Koch and Dikeman (1977), the distribution of muscle in retail cuts did not vary greatly by sire breed in the present study. However, the distribution of fat deposition in the carcass appears more variable by breed as demonstrated by differences in BFT, percent KF, and marbling score (Charles and Johnson, 1976; Kempster et al., 1976). Warner-Bratzler shear force

The effects of sire breed and postmortem aging on the WBSF of ribeye steaks from purebred and crossbred Jersey steers are presented in Figure 1. There was no difference (P = 0.96) for the interaction between sire breed and postmortem aging period.

Ribeye steaks from SimAngus and Wagyu sired steers (2.48 and 2.39 kg, respectively) had a lesser (P ≤ 0.01) WBSF value compared to ribeye steaks from Angus and Jersey sired steers (2.76 and 2.71 kg, respectively). Postmortem aging improved tenderness, with a lesser (P ≤ 0.01) WBSF value for ribeye steaks aged 14 d compared to 7 d (2.53 vs. 2.98 kg, respectively). Aging steaks until 21 and 28 d (2.42 kg) postmortem did not result in significant (P > 0.37) improvements in tenderness when compared with postmortem aging at 14 d. The USDA AMS (ASTM, 2011) maintains specific standards for “tender” (< 4.4 kg WBSF) and “very tender” (< 3.9 kg WBSF) label claims made for steaks. As demonstrated by Figure 1, on average, ribeye steaks from the steers in the present study, regardless of sire breed, would qualify for USDA very tender certification. Steaks from 85.2% of the cattle in the present study would qualify for the USDA AMS labeling claim “very tender” after 7 days of postmortem aging and 96.3% would qualify after 14 days of postmortem aging. Cole et al. (1964) reported purebred Jersey loin steaks had the lowest WBSF value when compared with many different breeds of cattle (Hereford, Angus, Brahman and cross, Santa Gertrudis, Holstein, and Charolais cross), but were not significantly different from Hereford, Brahman cross, or Holstein steers. Arnett et al. (2012) investigated the WBSF value of strip loin steaks from purebred Jersey steers offered either a high forage (24%) or low forage (12%) finishing ration compared to commodity beef strip loin steaks when aged for 18 d postmortem. Results from Arnett et al. (2012) demonstrated a greater WBSF value from the commodity beef strip loin steaks (3.12 kg) compared to strip loin steaks from the purebred Jersey steers (2.62 and 2.64 kg). Bumsted et al. (2014) compared the WBSF value of strip loin steaks from Limousin × Jersey steers to Certified Angus Beef strip loin steaks. Certified Angus Beef strip loin steaks had a lesser WBSF value compared to strip loin steaks from Limousin × Jersey steers (Bumsted et al., 2014). In disagreement with the results of the present study, Radunz et al. (2009) reported a similar WBSF value of strip loin steaks from Angus and Wagyu sired cattle at 3 d (4.3 kg) and 14 d (3.2 and 3.1 kg, for Angus and Wagyu sired cattle, respectively) of postmortem aging. Overall, data from the present study and

37 previously published literature indicate purebred and crossbred Jersey steers can produce steaks that are very tender in comparison to other breeds of cattle and the beef industry average. Longissimus fatty acid composition

The fatty acid composition of purebred Jersey and crossbred Jersey steers were evaluated for the effect of sire breed (Table 5). Total lipid percentage tended (P = 0.10) to be affected by sire breed, with muscle from Angus sired steers having a numerically greater percentage compared to muscle from Jersey sired steers. Muscle from SimAngus and Angus sired steers tended (P = 0.06) to have a greater percentage of palmitic acid (16:0) compared to Jersey sired steers. The percentage of myristic acid (14:0) tended (P = 0.10) to be affected by sire breed, with muscle from Wagyu sired steers having a numerically greater percentage compared to muscle from Jersey sired steers. As a direct result, Wagyu sired steers tended (P = 0.09) to have the lowest desaturase (14) index compared to the other sire breeds. Linoleic acid (18:2) percentage tended (P = 0.06) to be affected by sire breed, with muscle from Jersey sired steers having a numerically greater percentage of 18:2 compared to muscle from Angus sired steers. As a result of a greater percentage of 18:2, Jersey sired steers had a greater (P ≤ 0.04) percentage of polyunsaturated fatty acids (PUFA) in their muscle and a greater (P ≤ 0.02) ratio of PUFA to saturated fatty acids (SFA) compared to the muscle of Angus sired steers. The percentage of oleic acid (18:1cis9; r = 0.32; P ≤ 0.02), linoleic acid (18:2; r = -0.60; P ≤ 0.01), monounsaturated fatty acid (MUFA; r = 0.34; P ≤ 0.02), PUFA (r = -0.59; P ≤ 0.01), and PUFA:SFA (r = -0.50; P ≤ 0.01) were significantly correlated with the percentage of total lipid found in the muscle. When the fatty acid composition was adjusted to a similar total lipid percentage, there were no significant (P > 0.13) sire breed effects observed for the percentage of 18:1cis9, 18:2, MUFA, PUFA, and the PUFA:SFA ratio. Jiang et al. (2013) reported the total lipid percentage (6.21%) and fatty acid composition of muscle and various adipose depots of purebred Jersey steers. The fatty acid composition of muscle from purebred Jersey steers reported by Jiang et al. (2013)

38 was very similar to the results found in the present study. Previous research comparing different breeds of cattle report Jersey cattle as having unique and desirable fat characteristics, such as a greater percentage of MUFA, which results in softer fat. Siebert et al. (1996) reported greater percentages of intramuscular fat for early maturing cattle breeds, including Jerseys, compared to later maturing cattle breeds (Simmental, Charolais). Siebert et al. (1996) reported along with greater intramuscular fat content, there was an increase in the percentage of neutral lipids, particularly MUFA as palmitoleic (16:1) and oleic (18:1) acids and a decrease in the percentage of PUFA, specifically linoleic (18:2) acid. Pitchford et al. (2002) reported Jersey sired cattle to have a similar index of desaturation to Wagyu sired cattle, but a greater index when compared to cattle from other sire breeds (Angus, Hereford, South Devon, Limousin, and Belgian Blue). As a result of a greater index of desaturation, Jersey and Wagyu sired cattle had a greater percentage of MUFA, which resulted in a lesser fat melting point compared to cattle from other sire breeds (Pitchford et al., 2002). The findings of Pitchford et al. (2002) are supported by the results of Siebert et al. (2003) when they compared Jersey and Limousin sired cattle. Jersey sired cattle had a greater percentage of intramuscular fat, desaturase enzyme activity, MUFA, and a lesser fat slip point, indicating softer fat compared to Limousin sired cattle (Siebert et al., 2003). However, as mentioned previously by Siebert et al. (1996) and herein, when intramuscular fat content is adjusted to a similar level, the fatty acid composition of different breeds of cattle is quite similar if cattle are fed and managed the same. Value-added potential

Niche markets for beef products commonly establish well defined labeling criteria that have a real or perceived positive effect on characteristics related to eating quality, sustainability, management or rearing practices, human health benefits, and other attributes desired by the consumer. Niche markets can provide an opportunity to add value to beef products that meet these previously mentioned intrinsic and extrinsic characteristics desired by the consumer. A goal of the present study was to evaluate the potential use of labeling claims for value-added opportunities created from implementing

39 a crossbreeding program between Jersey cows and a terminal beef sire. The present study demonstrates the feasibility, and inherent opportunities and challenges encountered when raising purebred and crossbred Jersey steers to market ready weights without the use of exogenous growth promoting technologies (e.g. hormone implants and β-agonists), while meeting a consumer desire for beef raised without the use of exogenous growth promoting technologies. Lusk and Fox (2002) reported that 85% of consumers in the U.S. would prefer mandatory labeling of beef administered exogenous hormones; however, only 68% of consumers were willing to pay a premium for beef with this type of labeling. Their results demonstrated the average consumer would be willing to pay a 17% greater price for beef labeled with exogenous hormone use status, and consumers with a greater concern about the safety of exogenous hormone use were willing to pay greater than a 17% price increase (Lusk and Fox, 2002). Feeding dairy cattle for beef production, including Jersey influenced cattle, would provide a greater opportunity to account for the traceability of beef products. Dickinson and Bailey (2002) reported U.S. consumers would be willing to pay an additional $0.23 for a $3 roast beef sandwich if the beef was traceable. Consumers were willing to pay an additional $0.50, $0.63, or $1.06 for added assurances for animal welfare, food safety, or all three extrinsic factors, respectively (Dickinson and Bailey, 2002). Purebred Jersey steers in the present study demonstrated the ability to deposit marbling to achieve a USDA QG of Average Choice across the population of cattle studied. Implementing a crossbreeding program between Jersey cows and a terminal beef sire selected for marbling ability, as in the present study, produced crossbred Jersey steers with average USDA QG of Low Prime/High Choice. Marbling or intramuscular fat is a factor contributing to beef eating satisfaction, and as a result, is used to determine the USDA QG of beef. A consumer laboratory sensory panel comparing high marbling (upper 2/3 Choice, 8.81% fat) and low marbling (Select, 6.05% fat) strip steaks, with a similar WBSF value, rated greater flavor, juiciness, and overall acceptability scores for high marbled strip steaks compared to low marbled strip steaks (Killinger et al., 2004). Of the consumers (33%) with consistent acceptability ratings, 71% found high marbling

40 beef to be more acceptable (Killinger et al., 2004). As a result, consumers were willing to pay more for a steak with the amount of marbling they preferred, $2.49 and $3.24/kg for high marbled steaks by consumers from Chicago and San Francisco, respectively (Killinger et al., 2004). Platter et al. (2005) also reported U.S. consumers would be more willing to purchase and willing to pay an additional $0.89 and $2.47/kg for Premium Choice (upper 2/3 Choice) and Prime strip steaks, respectively, when compared to Select strip steaks. Jersey influenced steers from the present study produced ribeye steaks that would qualify for the USDA AMS labeling claim “very tender” (< 3.9 kg WBSF) after 7 d of post mortem aging. This finding provides strong evidence for Jersey influenced steers to meet niche markets with tenderness based claims. Miller et al. (2001) reported that U.S. consumers are able to differentiate beef tenderness, with WBSF values of < 3.0, < 3.4, and < 4.9 resulting in tenderness acceptability 100, 99, and 37-59% of the time, respectively. U.S. consumers (78%) would also be willing to pay a premium price for a guaranteed tender steak (Miller et al., 2001). In disagreement with reports from Miller et al. (2001), Lusk et al. (2001) reported 69% of consumers preferred tender steak, but only 36% were willing to pay a premium to receive a guaranteed tender steak. However, when tenderness status (tender, < 15 kg SSF vs. tough, >35 kg SSF) was revealed to the consumer, of the 84% of consumers preferring tender steaks, only 51% were willing to pay a premium for a guaranteed tender steak (Lusk et al., 2001). The average willingness to pay for a guaranteed tender steak was $2.71 and $4.06/kg if the tenderness status was unknown or known by the consumer, respectively. Data reported by Miller et al. (2001) demonstrate a $0.37/kg increase in price for every 1.0 kg decrease in WBSF. In agreement, Platter et al. (2005) reported an even greater increase ($1.02/kg) in the willingness of U.S. consumers to pay a premium for every 1.0 kg decrease in WBSF. Overall, an apparently large percentage of U.S. consumers would be willing to pay a premium for beef labeled as “very tender”, of which the Jersey influenced steers from the present study would certainly qualify.

Many consumers have negative connotations about fat affecting their health and make their meat purchasing decisions based on leanness (Grunert et al., 2004). As a result, some consumers are sacrificing some of the desired eating quality characteristics (flavor, juiciness, tenderness) of a highly marbled steak by choosing to purchase steaks from the retailer with a lesser degree of marbling. As mentioned in the discussion previously, as the level of marbling or intramuscular fat deposition increases, the proportion of MUFA, as oleic acid, increases as well. Research regarding the consumption of highly marbled beef has reported health benefits, such as increasing the plasma high density lipoprotein-cholesterol (HDL), while decreasing the plasma low density lipoprotein-cholesterol (LDL) in human subjects resulting in improved cardiovascular health (Adams et al., 2010, Gilmore et al., 2011; Gilmore et al., 2013; Crouse et al., 2016). While nutritional requirements are different for each individual person, the consumption of highly marbled Jersey influenced beef may have potential health benefits. Although, future research is warranted to make such labeling claims. Implications

Raising Jersey dairy steers for beef production can be economically challenging for producers and cattle feeders due a lesser ADG and feed efficiency compared to commercial beef cattle. In addition to inferior feedlot performance, Jersey steers are finely muscled and have extremely low retail yields compared to commercial beef cattle. A crossbreeding program between Jersey dairy cows with a terminal beef sire, as reported in the present study, resulted in improved feedlot performance and retail yield for crossbred Jersey steers compared to purebred Jersey steers, although still inferior to commercial beef cattle in the U.S. beef industry. To decrease the gap between Jersey influenced cattle and commercial beef cattle, terminal sire selection must consider growth rate and muscling ability. While not an aim of the present study, the use of exogenous growth promoting technologies (e.g. hormone implants and β-agonists) may be used to improve the growth rate and retail yield of Jersey influenced cattle; however, their use may negatively affect marbling deposition and tenderness. Therefore, the use of grow promoting technologies may limit value-added opportunities in niche markets (e.g. non-

42 hormone treated cattle) driven by meeting consumer desires. Additional research is needed to quantify the effects of feedlot performance, carcass yield, and carcass quality for Jersey influenced cattle raised with the use of growth promoting technologies. Overall, crossbred Jersey steers raised in the present study have demonstrated added value to participants in the beef and dairy industries with improved feedlot performance and carcass composition compared to purebred Jersey steers.

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Table 1. Composition of diets offered during the experiment

Finishing Finishing Item Receiving Growing Corn Silage Soy Hulls Ingredient ------DM basis ------Whole shelled corn 15.00 20.00 50.00 55.00 DDGS 15.00 20.00 20.00 15.00 Soy hulls 0.00 0.00 0.00 20.00 Corn silage 60.00 50.00 20.00 0.00 Supplement 10.00 10.00 10.00 10.00 Ground corn 2.26 4.07 5.77 5.77 Urea 0.50 0.50 0.50 0.50 Soybean meal 5.45 2.00 1.00 1.00 Limestone 0.72 1.80 1.10 1.10 Dicalcium Phosphate 0.11 0.00 0.00 0.00 White salt 0.16 0.50 0.50 0.50 Vit. A, 30,000 IU/g 0.01 0.01 0.01 0.01 Vit. D, 3,000 IU/g 0.01 0.01 0.01 0.01 Vit. E, 44 IU/g 0.02 0.02 0.02 0.02 Calcium Sulfate 0.40 0.70 0.70 0.70 Selenium, 201 ppm 0.02 0.04 0.04 0.04 Rumensin 90 1 0.01 0.02 0.02 0.02 Potassium Chloride 0.30 0.30 0.30 0.30 Cobalt Carbonate 0.00 0.01 0.01 0.01 Copper Sulfate 0.01 0.02 0.02 0.02 Zinc Sulfate 0.02 0.01 0.01 0.01 Magnesium Sulfate 0.01 0.00 0.00 0.00

Analyzed composition Crude protein, % 12.80 12.95 13.75 13.40 NDF, % 26.47 24.71 16.78 21.75 Fat, % 2.63 2.79 3.50 2.96 Ca, % 0.55 0.80 0.65 0.72 P, % 0.37 0.38 0.37 0.33 NEm, Mcal/kg 1.95 2.05 2.15 2.08 NEg, Mcal/kg 1.30 1.39 1.47 1.49 1 Elanco Animal Health (Greenfield, IN).

Table 2. Effect of terminal sire breed on the feedlot performance of purebred and crossbred Jersey steers adjusted to a similar initial body weight (210 kg)

Sire Breed Jersey Angus SimAngus Wagyu Item (n = 21) (n = 9) (n = 10) (n = 15) SEM 1 P-value Initial weight, kg 222 d 224 d 198 e 194 e 9.9 0.01 Age at receiving, d 2 257 d 227 e 212 e 231 e 10.1 0.01

Average daily gain, kg/d 0.85 e 1.05 d 1.08 d 0.97 d 0.0444 0.01 Daily dry matter intake, kg/d 2 6.67 f 7.72 d 7.35 de 6.80 ef 0.267 0.01 Total dry matter intake, kg 2 2316 2335 2304 2217 170.4 0.62 Gain:feed, kg/kg 2 0.123 b 0.133 ab 0.135 ab 0.142 a 0.0059 0.03

Days on feed, d 2 346 d 304 f 314 ef 331 e 17.0 0.01 Age at harvest, d 602 d 533 e 539 e 562 e 21.5 0.01 50 2 e d d d

Off-test weight, kg 499 531 548 532 15.4 0.01 a-c Sire breed lsmean estimates within a row with a different superscript differ (P ≤ 0.05). d-f Sire breed lsmean estimates within a row with a different superscript differ (P ≤ 0.01). 1 The reported standard error of the mean is the greatest between the sire breeds. 2 Variables were standardized to a common weight (210 kg) using initial weight as a linear covariate.

Table 3. Effect of sire breed on carcass characteristics of purebred and crossbred Jersey steers adjusted to a similar hot carcass weight (319 kg)

Sire Breed Jersey Angus SimAngus Wagyu Item (n = 20) (n = 9) (n = 10) (n = 15) SEM 1 P-value Final weight, kg 496 520 515 502 17.8 0.36 Hot carcass weight, kg 304 b 334 a 332 a 317 ab 11.8 0.02 Dressing percent, % 61.24 e 64.19 d 63.93 d 63.20 d 0.428 0.01 Fat thickness, cm 0.86 e 1.37 d 1.04 e 0.97 e 0.160 0.01 Longissimus muscle area, cm2 2 70.3 73.6 73.6 76.4 3.72 0.12 Kidney fat, % 7.89 d 5.28 f 6.48 e 6.43 e 0.451 0.01 Calculated Yield grade 3 4.06 3.88 4.01 3.59 0.233 0.16 Calculated BCTRC, % 4 47.39 47.77 47.48 48.47 0.541 0.16 Marbling score 5 586 b 745 a 651 ab 687 a 63.0 0.03

Quality grade 6 11.4 b 13.0 a 12.0 ab 12.3 ab 0.631 0.04 51

% Prime + 0.0 11.1 0.0 13.3 0.105 1.00 % Prime o 5.0 33.3 10.0 13.3 0.157 0.30 % Prime - 10.0 22.2 40.0 20.0 0.139 0.35 % Choice + 25.0 33.3 20.0 26.7 0.157 0.93 % Choice o 35.0 0.0 10.0 13.3 0.107 0.38 % Choice - 25.0 0.0 10.0 13.3 0.010 0.74 % Select + 0.0 0.0 10.0 0.0 0.095 1.00

Continued

Table 3. Continued

Lean color L* 41.4 f 46.9 d 43.8 e 44.7 e 0.748 0.01 a* 25.1 f 25.8 ef 26.9 d 26.4 de 0.416 0.01 b* 8.5 10.0 9.7 10.9 0.961 0.12 Fat color L* 71.7 73.0 73.7 72.2 1.255 0.29 a* 13.7 14.7 12.4 14.1 0.978 0.36 b* 18.3 e 21.3 d 18.1 e 18.6 e 0.735 0.01 a-c Sire breed lsmean estimates within a row with a different superscript differ (P ≤ 0.05). d-f Sire breed lsmean estimates within a row with a different superscript differ (P ≤ 0.01). 1 The reported standard error of the mean is the greatest between the sire breeds. 2 Variables were standardized to a common weight (319 kg) using hot carcass weight as a linear covariate. 3 Yield grade = 2.5 + (2.5 × (fat thickness / 2.54)) + (0.2 × kidney, pelvic, heart fat) + (0.0038 × (hot carcass

5 weight / 0.453592)) - (0.32 × (Longissimus muscle area / 6.4516)). 2 4 BCTRC (Boneless closely trimmed retail cuts) = 51.34 - (2.28 × (fat thickness)) - (0.462 × %kidney fat) - (0.02 × (hot carcass weight)) + (0.1147 × (Longissimus muscle area)). 5 Marbling score is based on a numeric scale: 500-599 = modest, 600-699 = moderate, 700-799 = slightly abundant. 6 Quality grade is based on a numeric scale: 11 = Average Choice, 12 = High Choice, 13 = Low Prime.

Table 4. Effect of sire breed on the distribution of carcass weight into retail cuts from purebred and crossbred Jersey steers adjusted to a similar chilled carcass side weight (154 kg)

Sire Breed Jersey Angus SimAngus Wagyu Item (n = 20) (n = 9) (n = 10) (n = 15) SEM 1 P-value Side weight, kg 147.6 b 162.1 a 161.1 a 153.8 ab 5.59 0.02 Total red meat, kg 23 83.3 b 84.8 ab 87.8 a 88.6 a 3.03 0.01 Retail yield, % 4 33.67 f 34.42 ef 35.72 de 36.28 d 1.058 0.01 Total red meat yield, % 3 54.03 f 54.67 ef 56.55 de 57.25 d 2.016 0.01 Fat yield, % 24.08 24.45 22.86 21.47 2.238 0.07 Bone yield, % 20.96 20.00 19.97 21.12 0.684 0.37 Chuck, kg 2 12.61 b 13.42 ab 14.33 a 13.64 ab 0.986 0.05 Shoulder clod, kg 2 3.47 b 4.08 ab 4.60 a 4.00 ab 0.580 0.02 Top blade, kg 2 1.39 1.45 1.75 1.52 0.129 0.12

Clod teres major, kg 0.43 0.42 0.39 0.49 0.059 0.42 5

3 2

Chuck tender, kg 0.95 0.96 0.95 1.03 0.063 0.16 Boneless chuck roll – 6.36 6.52 6.70 6.59 0.357 0.68 5.08×5.08 cm tail, kg 2 Brisket Brisket, kg 2 4.69 e 5.71 d 4.83 e 4.51 e 0.292 0.01 Rib, kg 2 6.47 6.60 6.54 6.67 0.197 0.81 Ribeye roll, kg 2 4.78 4.99 4.94 4.98 0.172 0.67 Back-ribs, kg 1.66 1.62 1.63 1.66 0.115 0.97

Continued

Table 4. Continued

Plate Skirt steak-inside, kg 2 0.58 0.65 0.66 0.53 0.082 0.42 Skirt steak-outside, kg 2 0.38 b 0.36 b 0.48 a 0.35 b 0.040 0.03 Loin, kg 2 10.54 e 10.64 e 10.98 e 12.05 d 0.334 0.01 Short loin, kg 2 7.77 e 7.98 e 8.22 de 8.57 d 0.243 0.01 Striploin – 2.54 cm tail, kg 2 4.09 e 4.29 e 4.28 e 4.74 d 0.214 0.01 Tenderloin tail, kg 2 0.89 0.83 0.95 0.94 0.065 0.14 Tenderloin butt, kg 0.96 1.00 1.06 1.01 0.058 0.58 Top sirloin butt (boneless), kg 2 2.76 b 2.65 b 2.90 ab 3.22 a 0.164 0.01 Top sirloin butt cap, kg 2 0.68 b 0.64 b 0.73 a 0.80 a 0.052 0.04 Bottom sirloin ball tip, kg 0.39 0.61 0.54 0.56 0.199 0.31 Bottom sirloin tri-tip, kg 2 0.70 b 0.68 b 0.70 b 0.83 a 0.607 0.03 Flank 2

5 Flank steak, kg 0.66 0.63 0.70 0.66 0.026 0.21 4 Round, kg 2 16.12 ef 15.06 f 16.73 de 17.66 d 0.546 0.01 Knuckle (peeled), kg 2 3.76 3.36 3.85 3.97 0.200 0.11 Inside round (boneless), kg 2 6.86 e 6.51 e 7.03 e 7.68 d 0.271 0.01 Bottom round eye, kg 2 1.50 b 1.48 b 1.70 a 1.59 ab 0.099 0.02 Bottom round flat, kg 2 3.99 e 4.13 e 4.13 e 4.44 d 0.173 0.01

Continued

Table 4. Continued

Lean trim - fore, kg 2 21.31 20.23 22.13 21.36 1.128 0.28 Lean trim - hind, kg 9.46 b 11.59 a 10.66 a 10.70 a 0.642 0.05 Total lean trim, kg 2 31.05 31.56 32.51 32.14 1.412 0.42 Fat trim - fore, kg 2 12.58 b 15.85 a 12.78 b 11.67 b 2.061 0.02 Fat trim - hind, kg 25 25.40 a 21.70 b 22.04 b 21.82 b 1.519 0.03 Kidney fat, kg 2 12.19 d 7.88 e 9.78 e 9.97 e 0.626 0.01 Total fat trim, kg 2 37.98 a 37.47 a 34.85 ab 33.41 b 3.182 0.04 Bone - fore, kg 2 20.30 19.25 19.61 20.13 1.123 0.89 Bone - hind, kg 2 11.80 11.79 11.42 12.49 0.786 0.68 Total bone, kg 2 32.11 31.01 31.04 32.59 1.126 0.57 a-c Sire breed lsmean estimates within a row with a different superscript differ (P ≤ 0.05). d-f Sire breed lsmean estimates within a row with a different superscript differ (P ≤ 0.01). 1 The reported standard error of the mean is the greatest between the sire breeds.

5 2

5 Variables were standardized to a common weight (154 kg) using chilled carcass side weight as a linear covariate.

3 Total red meat yield is the sum of the boneless closely trimmed retail cuts and lean trimmings. 4 Retail yield refers to boneless closely trimmed retail cuts. 5 Fat trim from the hind quarter includes the kidney fat.

Sire Breed (P ≤ 0.01) 3.4 Postmortem Aging (P ≤ 0.01) Sire Breed × Postmortem Aging (P = 0.95) 3.2 3.0 2.8 2.6 WBSF, kg WBSF, 2.4 2.2 2.0 7 14 21 28

Postmortem aging, d

Jersey Angus SimAngus Wagyu

Table 5. Effect of sire breed on the fatty acid composition (%) of the longissimus muscle from purebred and crossbred Jersey steers Sire Breed Jersey Angus SimAngus Wagyu Item (n = 20) (n = 9) (n = 10) (n = 15) SEM 1 P-value Total fatty 64.6 92.8 72.1 74.3 11.0 0.09 acids, mg/g Total lipid, % 6.46 9.28 7.21 7.43 1.10 0.09

14:0, % 3.45 3.50 3.63 3.87 0.220 0.09 14:1, % 1.21 1.25 1.23 1.08 0.149 0.56 16:0, % 25.91 27.30 27.45 26.84 0.541 0.06 16:1, % 5.00 4.37 4.88 5.34 0.407 0.26 18:0, % 11.32 11.35 10.99 10.72 0.366 0.37 18:1 trans, % 2.85 3.32 3.45 3.66 0.588 0.15 18:1 cis 9, % 39.92 39.95 38.21 38.31 1.188 0.17 18:1 cis others, % 2.66 2.56 2.36 2.66 0.250 0.46 18:2, % 3.79 3.28 3.55 3.51 0.155 0.06 18:3, % 0.14 0.09 0.11 0.12 0.030 0.23

SFA, % 40.69 42.08 42.07 41.38 0.732 0.28 MUFA, % 51.64 51.49 50.13 51.07 0.825 0.45 PUFA, % 3.93 a 3.38 b 3.66 ab 3.63 ab 0.156 0.04 MUFA:SFA 1.279 1.226 1.194 1.240 0.042 0.37 PUFA:SFA 0.097 a 0.080 b 0.087 ab 0.088 ab 0.004 0.02 Desaturase 25.63 25.77 24.92 21.62 1.787 0.09 index (14) 2 Desaturase 16.12 13.80 15.00 16.50 1.004 0.12 index (16) 2 Desaturase 77.85 77.92 77.62 78.14 0.796 0.95 index (18) 2 a-c Sire breed lsmean estimates within a row with a different superscript differ (P ≤ 0.05). 1 The reported standard error of the mean is the greatest between the sire breeds. 2 Index of delta desaturase enzyme activity on the conversion of 14:0 to 14:1, 16:0 to 16:1, and 18:0 to 18:1 cis 9 [e.g. = 100 × (18:1 cis 9 / (18:0 + 18:1 cis 9))].

Chapter 4. Evaluation of feedlot performance, carcass characteristics, carcass retail cut distribution, Warner-Bratzler shear force, and fatty acid composition of crossbred Jersey steers and heifers

ABSTRACT

Objective: This experiment investigated the effects of sire breed and sex on the feedlot performance, carcass yield, fatty acid composition, and tenderness of crossbred Jersey cattle. Materials and Methods: Crossbred Jersey steers and heifers sired by Angus (n = 9, 11), SimAngus (n = 10, 19), and Red Wagyu (n = 15, 7) bulls were used in a randomized complete block design. Results: Adjusted to a similar initial BW, Angus- and SimAngus-sired cattle had a greater ADG (P ≤ 0.01) and average daily DMI (P ≤ 0.01), resulting in a greater off-test BW (P ≤ 0.04) and fewer days on feed (P ≤ 0.01) compared to Wagyu-sired cattle. At a similar adjusted HCW, carcasses from Angus-sired cattle had a greater fat thickness (P ≤ 0.01) and less kidney fat (P ≤ 0.01) compared to carcasses from SimAngus- and Wagyu- sired cattle. Sire breed did not affect total red meat yield (P = 0.32), fat yield (P = 0.28), and bone yield (P = 0.35). Warner-Bratzler shear force values were greater (P ≤ 0.01) for steaks from Angus-sired cattle compared to steaks from SimAngus- and Wagyu-sired cattle. Steaks from Angus-sired cattle had a greater marbling score (P ≤ 0.01) and percentage of total lipid (P ≤ 0.01) compared to steaks from SimAngus- and Wagyu-sired cattle. Applications: Appropriate selection of a terminal sire breed will depend upon where the producer intends to sell in the production chain, as different sire breeds excel in different growth and carcass traits.

INTRODUCTION

Jersey cattle are smaller framed, slower growing, and finely muscled compared to other breeds of cattle, especially beef cattle breeds (Cole et al., 1964; Koch et al., 1976). As a result, the sale of purebred Jersey male calves provide very little economic return to Jersey producers due to the anticipated poor growth and light finishing weights of purebred Jersey steers in the feedlot. In addition, fattened purebred Jersey steers also receive dairy-type discounts for light muscling when sold to the packing plant. These negative economic factors have resulted in little to no demand for purebred Jersey steers in the commercial beef industry. However, Jersey cattle produce high quality beef with a superior eating satisfaction. Jersey steers were reported to have the greatest tenderness, flavor, and juiciness scores for loin and round steaks when assessed by both a laboratory and family panel (Cole et al., 1964; Ramsey et al., 1963). A trained sensory panel described by Arnett et al. (2012) reported greater tenderness, juiciness, beef flavor intensity, and overall acceptability scores for strip steaks from Jersey steers compared to commodity strip steaks representing U.S. commodity boxed beef. Therefore, Jersey beef may be more suitable for niche markets or value-added markets, such as white tablecloth restaurants and export markets that demand high quality beef products with superior eating satisfaction compared to the U.S. commodity beef market. The present study was designed to investigate the use of different terminal sire breeds in a crossbreeding program with Jersey cows for the production of a high quality beef product to be sold into value-added markets that restrict the use of exogenous growth promoting technologies (e.g. hormone implants and β-agonists). It was hypothesized that sire breed selection would affect the overall profitability of crossbred Jersey offspring throughout the production chain. The objectives of the present study were to evaluate economically relevant measures in the feedlot, carcass composition, carcass quality, and instrumental indicators of beef eating quality to assess the potential opportunities to add value to crossbred Jersey offspring in different sectors of the beef production chain.

MATERIALS AND METHODS

Crossbred Jersey steer and heifer calves were produced using Angus (1 sire), SimAngus (4 sires), and Red Wagyu (3 sires) bulls selected for calving ease and marbling ability. The study was conducted as a randomized complete block design over the course of 2 years (2015 and 2016), with year used as the block. Steers (n = 9, 10, and 15) and heifers (n = 11, 19, and 7) from the mating of Jersey cows to Angus, SimAngus, and Red Wagyu bull, respectively, arrived at the Ohio Agricultural Research and Development Center (OARDC) feedlot with an average initial BW of 203 ± 28 kg and an average age of 227 ± 19 d. The day after arrival, steer calves were weighed, ear-tagged, and vaccinated before being separated into individual pens. Each pen (2.6 × 1.5 m) consisted of concrete slatted floors, with a 1.5 m long concrete feed bunk, and supplied ad libitum access to clean fresh water. Feeding and management

Diets were formulated to meet the nutrient requirements of growing and finishing calves (NRC, 2000). Calves were offered a receiving diet for approximately 30 d, a growing diet for 70 d, and two finishing diets for the remainder of the study (Table 6). Feed allocation and feed refusals were weighed daily prior to feeding at 0930 to record individual feed intake. Feed samples were collected weekly to determine DM content (AOAC, 1984) and a composite sample of each dietary ingredient was analyzed for nutrient composition (Rock River Laboratory Inc., Wooster, OH). Initial BW was measured the day after arrival to the OARDC feedlot and off-test BW was recorded prior to removal of the cattle from the feedlot. The targeted endpoint for steers and heifers was a live BW of 523 and 500 kg, respectively. Cattle were 60 removed in groups of 6 to 8 for harvest at 14 d intervals as target endpoints were reached. Due to the duration of time on feed needed for cattle to reach the predetermined harvest endpoint, some cattle (primarily Wagyu crossbreds) had to be removed and harvested prior to reaching the target BW to provide feedlot pens for cattle the subsequent year. Carcass fabrication

Cattle were transported to The Ohio State University abattoir (Columbus, Ohio) for harvest. The following day cattle were harvested and final BW and HCW were recorded. After carcasses chilled for 7 d at 4 ºC, chilled carcass weight was recorded and carcasses were ribbed between the 12th and 13th ribs to measure fat thickness (FT), LM area (LMA), carcass maturity, marbling score, USDA QG, USDA YG, and percent boneless closely trimmed retail cuts (BCTRC). A single measure for instrumental color (CIELAB L*, a*, and b*) was collected after a 30 min bloom time with a Konica Minolta colorimeter CR-410 (Minolta Company, Ramsey, NJ), with a 50-mm diameter aperture and D65 illuminant, calibrated against a white tile, on the LM at the 12th rib and subcutaneous fat over the 11th and 12th ribs. Carcass kidney fat (KF) percentage was determined by the removal and weighing of the kidney fat during the fabrication process, divided by the chilled side weight. The right side of each carcass was fabricated into primal and sub-primal beef cuts according to North American Meat Processors Association guidelines (NAMP, 2007) to determine carcass cut-out yield and distribution. The following primal and sub-primal weights were recorded: NAMP#112A ribeye roll, NAMP#124 back ribs, NAMP#114 shoulder clod, NAMP#114D top blade, NAMP#114F clod teres major, NAMP#116A chuck roll, NAMP#116B chuck tender, NAMP#120 brisket, NAMP#121D inside and NAMP#121E outside skirt steak, NAMP#167A knuckle, NAMP#168 top/inside round, NAMP#171B bottom round, NAMP#171C eye of round, NAMP#184 top sirloin butt, NAMP#184D top sirloin butt cap, NAMP#185B ball tip, NAMP#185D tri-tip, NAMP#191A butt tender, NAMP#192A tenderloin tail, NAMP#193 flank steak, 80:20 lean trim, fat trim, and bone weight.

Warner-Bratzler shear force

Four 2.54 cm thick steaks were cut from the posterior end of the ribeye roll and randomized to a postmortem aging period of either 7, 14, 21, or 28 d at 4 ºC, and subsequently frozen at -20 ºC. Prior to cooking, steaks were thawed over night at 4 ºC. Cooking and WBSF were conducted according to guidelines set by the American Meat Science Association (AMSA, 2015). Cooking temperature was monitored using a thermocouple probe (5.08 cm Mini Needle Probe, Thermoworks, American Fork, UT) and a thermocouple reader (ThermaData Thermocouple Logger KTC, Thermoworks, American Fork, UT). Steaks were cooked on a flat top grill set at 190 ºC, flipped at an internal temperature of 40 ºC, and removed at an internal temperature of 71 ºC. Steaks were allowed to cool over night at 4 ºC. The next day, six round cores (1.27 cm diameter) were collected parallel to the muscle fibers from each steak. Cores were sheared perpendicular to the muscle fibers with a WBS v-notch blade using a TA.XT2 plus texture analyzer (Texture Technologies Corp., Scarsdale, New York). The crosshead speed was set at 200 mm/min and the peak force required to shear the sample was recorded. Longissimus muscle fatty acid composition

Fatty acid extraction and methylation procedures used were from Folch et al. (1957) and Doreau et al. (2007), respectively. An approximately 20 g sample of LM, trimmed free of subcutaneous fat and connective tissue, was collected and frozen on d 7 from the ribeye roll for fatty acid composition analysis. Longissimus muscle samples were each ground in a blender to create a homogenous sample, from which 1 g of ground tissue was added to a pyrex tube containing a screw cap. In addition to the ground tissue, 2 ml of an internal standard (0.5 mg 19:0/ml; Nu-Chek Prep, Inc. Elysian, MN), 0.7 ml of 10N KOH in water, and 4.3 ml of methanol were added and vortexed for 120 s. Next, sample tubes were placed in a 55 ºC hot water bath for 90 min, with 5 s of rigorous shaking taking place every 20 min for each sample. Samples tubes were placed in an ice water bath to cool samples to room temperature before adding 0.58 ml of 24N H2SO4 to each sample tube. Sample tubes were mixed by inversion and placed back in the 55 ºC 62 hot water bath for 90 min, with 5 s of rigorous shaking taking place every 20 min for each sample once again. Afterwards, sample tubes were cooled again in an ice water bath before the addition of 3 ml of hexane. Sample tubes were vortexed and centrifuged (800 × g) at room temperature for 5 min. each, and then the hexane layer was extracted and placed in a gas chromatography vial to be analyzed. All fatty acid methyl esters were separated by gas-liquid chromatography using a CP-SIL88 capillary column (100 m x 0.25 mm x 0.2-μm film thickness). The indices of delta desaturation enzyme activity on the conversion of 14:0 to 14:1, 16:0 to 16:1, and 18:0 to 18:1 cis 9 were calculated as follows: [e.g. = 100 × (18:1 cis 9 / (18:0 + 18:1 cis 9))]. Statistical Analysis

Statistical analyses were performed using PROC MIXED in SAS (SAS Inst. Inc., Cary, NC), except when PROC CORR was used for determining the correlation between variables. The experimental design was a randomized complete block design with animal as the experimental unit. The statistical model used was: Yijk = μ + Bi + Sj + BSij + yk + eijk, where μ = the population mean estimate, Bi = sire breed, Sj = sex, and BSij = the interaction between the sire breed and sex as fixed effects, and the random effect of yj = year, and eijk = random error. The statistical model used for WBSF was: Yijklm = μ + Bi +

Sj + BSij + Pk + BPik + SPjk + BSPijk + yl + am + eijklm, where Pk = postmortem aging, BPik

= sire breed × postmortem aging, SPjk = sex × postmortem aging, and BPSijk = sire breed

× sex × postmortem aging as fixed effects, and the random effect of am = animal. The LSMEANS and PDIFF statements were used to record treatment least square mean estimates, standard errors, and distinguish differences between the treatment levels. When significant, initial BW, HCW, and chilled side weight were used as covariates for the feedlot performance data, carcass data, and cut-out data, respectively. A significance of fixed effects and covariates was established at P ≤ 0.05 and tendencies are discussed at 0.05 < P ≤ 0.10.

RESULTS AND DISCUSSION

Feedlot Performance

Angus-sired calves were heavier (P ≤ 0.01) at feedlot entry compared to SimAngus- and Wagyu-sired calves (Table 7); therefore, feedlot performance measures were standardized to a similar initial BW across sire breed and sex with a linear covariate (203 kg). Steer and heifer calves sired by Angus (225 and 229 d, respectively) and Wagyu (228 and 223 d, respectively) bulls entered the feedlot at a similar age (P > 0.43), but among SimAngus-sired claves, steer calves were younger (P ≤ 0.01) compared to SimAngus sired heifer calves (209 vs. 235 d, respectively; sire breed × sex interaction, P ≤ 0.02). Consequently, steer and heifer calves sired by Angus (0.89 and 0.88 kg/d, respectively) and Wagyu (0.89 and 0.91 kg/d, respectively) bulls had a similar WDA (P > 0.44), but among SimAngus-sired claves, steer calves had a greater (P ≤ 0.01) WDA compared to SimAngus-sired heifer calves (0.96 vs. 0.86 kg/d, respectively; sire breed × sex interaction, P ≤ 0.01). In disagreement, Casas et al. (2012) reported lesser pre- weaning ADG for Wagyu-sired calves compared to calves sired by British (Hereford and Angus) and Dairy (Norwegian Red, Swedish Red and White, and Holstein-Fresian) bulls. Prior management or raising practices of the calves before arrival to the feedlot was not controlled, and as a result, could have greatly influenced the pre-test growth rate of the calves. During the feeding trial, Angus- and SimAngus-sired cattle had a greater (P ≤ 0.01) ADG and average daily DMI compared to Wagyu-sired cattle, with Angus-sired cattle tending (P = 0.10) to have a greater average daily DMI compared to SimAngus- sired cattle (Table 7). Total DMI did not differ between steers and heifers sired by SimAngus (2270 and 2280 kg, respectively) and Wagyu (2192 and 2196 kg, respectively) bulls, but total DMI was numerically greater for Angus-sired steers compared to Angus- sired heifers (2405 vs. 2177 kg, respectively; sire breed × sex interaction, P = 0.06). Across the entirety of the feeding trial, G:F did not differ (P = 0.67) for cattle representing the different sire breeds. Wagyu-sired cattle required 34 and 23 more (P ≤ 0.01) days on feed (DOF) compared to Angus- and SimAngus-sired cattle, respectively. 64

Wagyu sired cattle were older (P ≤ 0.01) and had a lesser off-test BW (P ≤ 0.04) compared to Angus- and SimAngus-sired cattle. When comparing the feedlot performance of steers comprised of 0, 50, and 100% Simmental and Angus genetics, Retallick et al. (2013) reported ADG and G:F tended to be greater as the proportion of Simmental influence increased. The small number of sires representing each breed in the present study may explain the similar feedlot performance between Angus- and SimAngus-sired cattle. Furthermore, Radunz et al. (2009) reported a greater ADG and DMI for Angus-sired steers compared to Wagyu-sired steers; however, Wagyu-sired steers had a greater G:F compared to Angus-sired steers. Casas et al. (2007) and Casas and Cundiff (2006) reported bulls with Wagyu sires or maternal grandsires had a lesser post-weaning ADG compared to bulls from Angus sires or maternal grandsires. The authors acknowledge a more extensive evaluation of sires within each sire breed would be necessary to fully understand sire breed effects, focusing especially on within breed genetic information and ranking for performance traits of interest. During the feeding trial, steers had a greater DMI (P ≤ 0.01), ADG (P ≤ 0.01), and G:F (P ≤ 0.04) compared to heifers (Table 7). Moreover, steers were younger (P ≤ 0.04) and heavier (P ≤ 0.01) at harvest, while requiring fewer DOF (P ≤ 0.02) compared with heifers. These results are consistent with previous research demonstrating a greater rate of post-weaning gain, which resulted in a greater final BW for steers relative to heifers (Bradley et al., 1966; Thrift et al., 1970; Tanner et al., 1970). Carcass Characteristics

Carcass characteristics of crossbred Jersey steers and heifers were standardized to a similar HCW (319 kg) with the use of a linear covariate. Prior to adjustment, Angus- and SimAngus-sired steers had a greater (P ≤ 0.01) HCW compared to Wagyu-sired steers, whereas steers had a greater (P ≤ 0.01) HCW compared to heifers (Table 8). Prior to standardizing, final live BW was greater (P ≤ 0.01) for Angus- and SimAngus-sired cattle compared to Wagyu-sired cattle, and steers were heavier (P ≤ 0.01) compared to heifers. Dressing percentage tended (P = 0.06) to be greater for Angus-sired cattle than

SimAngus and Wagyu sired cattle, but dressing percentage did not differ (P = 0.11) between steers and heifers. Carcasses from Angus-sired cattle had a greater (P ≤ 0.01) FT compared to carcasses from SimAngus- and Wagyu-sired cattle, whereas carcasses from SimAngus- and Wagyu-sired cattle had a greater (P ≤ 0.01) KF percentage compared to carcasses from Angus-sired cattle. Neither LMA (P = 0.55), LMA:HCW (P = 0.84), calculated USDA YG (P = 0.84), and calculated percent BCTRC (P = 0.84) differed between carcasses from the different sire breeds. All carcasses were A-maturity (P = 0.23), marbling score and USDA QG were greater (P ≤ 0.01) for carcasses from Angus-sired cattle compared to carcasses from SimAngus- and Wagyu-sired cattle. When comparing the influence of Simmental and Angus genetics (0, 50, and 100%), Retallick et al. (2013) reported a greater FT and marbling score with an increasing percentage of Angus influence. Also, Koch et al. (1976) reported the greatest FT, second greatest percentage of intramuscular fat, and second lowest percentage of kidney fat for Angus-sired steers when compared to Hereford-, Jersey-, South Devon-, Limousin-, Charolais-, and Simmental-sired steers. More specifically, purebred Angus steers had a greater FT and longissimus intramuscular fat percentage and a lesser kidney fat percentage compared to SimAngus steers (Koch et al., 1976). Radunz et al. (2009) reported a similar FT at the 12th rib between Angus-sired and Black Wagyu-sired steers, but a lesser percentage of intramuscular fat at the 12th rib and percentage of kidney fat for Angus-sired steers. Inconsistencies between the results of the present study and the study of Radunz et al. (2009) may be due to breed differences between Black and Red Wagyu. Sasaki et al. (2006) reported Red Wagyu (Japanese Brown) have a lesser FT and marbling score compared to Black Wagyu (Japanese Black) cattle depending on their genetics (prefecture origin). Similar to results of the present study, Mir et al. (1999) did not report Wagyu as the sire breed with the greatest marbling score, as they reported that heavy-weight Continental crossbred steers had a greater marbling score compared to lighter weight crossbred Wagyu (50 and 75% influence) cattle. Retallick et al. (2013) reported greater LMA with the increasing influence of Simmental genetics relative to

Angus genetics and Radunz et al. (2009) reported a tendency for Wagyu-sired steers to have a greater LMA compared to Angus-sired steers. Carcasses from heifers had a greater FT (P ≤ 0.01) and percentage of kidney fat (P ≤ 0.01) at a similar HCW, resulting in a tendency for a greater calculated USDA YG (P = 0.07) and lesser calculated BCTRC (P = 0.07) relative to steer carcasses. Unlike sire breed, sex differences did not result in differences for the location of carcass fat deposition. Differences in carcass fat deposition between heifers and steers can be attributed to the earlier onset of fat deposition (Mukhoty et al., 1971) and the greater rate of fat deposition relative to muscle growth (Berg et al., 1979). Lean color of the LM was lighter (greater L* value; P ≤ 0.01) for Angus-sired cattle compared to Wagyu- and SimAngus-sired cattle. Lean color (L*) values demonstrated a pattern similar to marbling score, where carcasses from Angus-sired cattle, with a greater marbling score had greater L* values compared to carcasses from SimAngus- and Wagyu-sired cattle with a lesser marbling score. This resulted in a significant (P ≤ 0.01) positive correlation between lean CIELAB L* and marbling (r = 0.52) in the present study. Steers had lighter (P ≤ 0.05) lean color when compared to heifers, which is in agreement with results reported by Page et al. (2001). However, steers and heifers did not have different marbling scores (P = 0.35) in the present study; therefore, there appears to be an innate difference in lean L* color due to sex. SimAngus- and Wagyu-sired cattle had a redder (greater a* value; P ≤ 0.01) colored lean compared to Angus-sired cattle. There were no differences for lean CIELAB b* values (P = 0.85), fat CIELAB L* values (P = 0.12), and fat CIELAB a* values (P = 0.12) from carcasses between the sire breeds. Interestingly, there was a tendency for a sire breed × sex interaction (P = 0.10), where SimAngus-sired heifers (20.1) had a fat CIELAB b* value similar to Angus-sired steers (21.0) and heifers (20.8), while SimAngus-sired steers (18.1) had a lesser fat b* value similar to Wagyu-sired steers (18.4) and heifers (18.6). Additionally, fat CIELAB b* values were positively correlated (r = 0.35; P ≤ 0.01) with the FT of carcasses from crossbred Jersey cattle in the present study. Jersey cattle have been reported as having a higher frequency of the AA genotype for the β-carotene-9, 10-

67 dioxygenase (BCO2) gene, which leads to the loss of enzyme function and a greater accumulation of β-carotene in the carcass fat that results in the yellow fat color (Tian et al., 2010). It may be possible BCO2 enzyme activity decreased as the crossbred Jersey cattle in the present study deposited more fat, resulting in an accumulation of β-carotene, producing yellower fat at a greater stage of physiological maturity. Although, future research will be needed to test the hypothesis of changing BCO2 enzyme activity as cattle mature and deposit fat. Carcass Cut-Out Distribution

Chilled side weight was greater (P ≤ 0.01) for Angus- and SimAngus-sired cattle compared to Wagyu-sired cattle (158, 156, and 149 kg, respectively) and greater (P ≤ 0.01) for steers compared to heifers (160 and 149 kg, respectively; Table 9); and therefore, was standardized to a similar chilled carcass weight with the use of a linear covariate (154 kg). Within sire breed, steers and heifers of Angus- (35.1 and 34.2%) and SimAngus- (35.7 and 35.1%) sired cattle had a similar retail yield; however, Wagyu-sired steers had a numerically greater retail yield compared to Wagyu-sired heifers (36.2 and 34.4%; sire breed × sex interaction, P = 0.07). Sire breed did not affect (P > 0.28) the yield of retail cuts, total red meat, fat trim, and bone from beef carcasses. The retail weight of the chuck, as well as the shoulder clod (NAMP#114), top blade (NAMP#114D), clod teres major (NAMP#114F), chuck tender (NAMP#116B), and chuck roll (NAMP#116A), did not (P > 0.24) differ between sire breeds (Table 9). Weight of the brisket (NAMP#120) was greater (P ≤ 0.01) in carcasses of Angus‐sired cattle compared to carcasses of SimAngus‐ and Wagyu‐sired cattle. The retail weight of the rib, as well as the ribeye roll (NAMP#112A) and back ribs (NAMP#124) were similar (P > 0.23) between sire breeds. Additionally, the inside skirt steak (NAMP#121D) weight was greater (P ≤ 0.04) in carcasses from Angus‐ and SimAngus‐sired cattle than carcasses from Wagyu‐sired cattle and the outside skirt steak (NAMP#121E) weight tended (P = 0.06) to be greater in carcasses from SimAngus-sired cattle compared to Wagyu-sired cattle. Carcasses from SimAngus‐sired cattle had a greater (P ≤ 0.02) weight of lean trim from the fore-quarter compared to carcasses from Angus‐sired cattle;

68 though, carcasses from Angus-sired cattle had a greater (P ≤ 0.01) weight of fat trim from the fore-quarter compared to carcasses from SimAngus- and Wagyu-sired cattle. Sire breed had no effect (P = 0.65) on fore-quarter bone weight. Wagyu-sired steer carcasses had a greater (P ≤ 0.01) loin primal weight (12.0 kg) when compared to Angus- and SimAngus- sired steer carcasses (10.7 and 11.0 kg, respectively), but the loin primal weight of heifer carcasses did not differ (P > 0.08) across sire breed (11.2, 11.7, 11.4 kg for Angus-, SimAngus-, and Wagyu-sired heifers, respectively; sire breed × sex interaction, P ≤ 0.04). Weights of the boneless strip loin (NAMP#180), tenderloin butt (NAMP#191), bottom sirloin ball tip (NAMP#185B), and bottom sirloin tri‐tip (NAMP#185C) were similar (P > 0.20) between the different sire breeds. Top sirloin butt (NAMP#184) weights were greater (P ≤ 0.01) in carcasses from SimAngus‐ and Wagyu‐sired cattle compared to Angus‐sired cattle. Carcasses from SimAngus-sired cattle tended (P = 0.09) to have a greater tenderloin tail (NAMP#192A) weight compared to carcasses from Angus-sired cattle, whereas carcasses from Wagyu- sired cattle tended (P = 0.10) to have a greater bottom sirloin butt cap (NAMP#184D) weight compared to carcasses of Angus-sired cattle. The retail weight in the round from Angus-sired steer carcasses (14.9 kg) was less compared to all other steer and heifer carcasses [SimAngus-, and Wagyu-sired steers (16.7 and 17.6 kg) and Angus-, SimAngus-, and Wagyu-sired heifers (16.3, 16.7, and 17.1 kg), respectively; sire breed × sex interaction, P ≤ 0.05)]. Weight of the bottom round flat (NAMP#171B) was not affected (P = 0.43) by sire breed. However, carcasses from SimAngus‐ and Wagyu‐sired cattle had greater (P ≤ 0.03) knuckle (NAMP#167) weights compared to carcasses from Angus‐sired cattle, whereas inside round weights were greater (P ≤ 0.01) in carcasses from Wagyu‐sired cattle compared to Angus- and SimAngus‐sired cattle. Weight of the eye of round (NAMP#171C) was lesser from carcasses of Angus-sired steers when compared to Angus-sired heifer carcasses (1.48 vs. 1.70 kg), and carcasses from SimAngus- (1.70 and 1.72 kg) and Wagyu-sired (1.58 and 1.54 kg) cattle (sire breed × sex interaction, P ≤ 0.03). Carcasses from Angus-sired cattle tended (P = 0.09) to have a greater weight of lean trim from the hind-quarter compared to carcasses from SimAngus-

69 and Wagyu-sired cattle, while Angus-sired cattle had less (P ≤ 0.01) kidney fat compared to SimAngus- and Wagyu-sired cattle. Sire breed had no effect (P = 0.81) on hind- quarter bone weight. When comparing cutout yields between different sire breeds (Hereford, Angus, Jersey, South Devon, Charolais, Limousin, and Simmental sires mated to Hereford and Angus dams), Koch and Dikeman (1977) reported that Simmental-sired steers produced carcasses with greater chuck (21.0 vs. 19.7%), loin (10.3 vs. 9.7%), and round (18.1 vs. 16.3%) yields compared to carcasses from Angus-sired steers, but primal brisket (2.6 vs. 2.7%) and rib (6.4 vs. 6.2%) yields were similar between Angus- and Simmental-sired steer carcasses. It may be presumed that SimAngus-sired cattle would be intermediate between Angus- and Simmental-sired cattle for retail carcass yield, which may explain a lack of observed differences between Angus- and SimAngus-sired cattle in the present study. The relatively new incorporation of Wagyu genetics into the United States, along with their limited use in commercial production systems, has likely resulted in a paucity of research on carcass cut-out parameters of Wagyu influenced cattle compared with other sire breeds. In addition, much of the current results regarding carcass cutability are estimated from equations. Wheeler et al. (2004) reported estimates of carcass tissue yields from ribeye roll composition analysis and reported similar retail product weight, fat weight, and bone weight between Angus-sired and Wagyu- (Black and Red) sired steers when compared at a similar HCW. Graham et al. (2009) and McKiernan et al. (2009) reported estimated carcass meat yields from different sire breeds and sires selected for marbling or meat yield using VIAscan image analysis. The estimated carcass meat yields for carcasses from Angus sires selected for retail yield were greater compared to both carcasses from Angus sires selected for marbling ability and carcasses from Red Wagyu sires (Graham et al., 2009). In disagreement with Graham et al. (2009), McKiernan et al. (2009) reported greater estimated carcass meat yields from carcasses sired by Red Wagyu when compared to carcasses sired by Angus selected for marbling ability, but did not report any difference in meat yield when comparing carcasses from Red Wagyu sires and carcasses sired by Angus sires selected specifically for greater retail

70 yield. The results from Graham et al. (2009) and McKiernan et al. (2009) demonstrate the importance of sire selection criteria within a breed when attempting to compare different breeds of cattle. Steer carcasses had greater total red meat (P ≤ 0.05) and bone (P ≤ 0.02) yields, but a lesser (P ≤ 0.01) fat trim yield when compared to heifer carcasses (Table 9). The weight of the chuck primal, and more specifically, the top blade (NAMP#114D), were greater (P ≤ 0.02) in steer carcasses compared to heifer carcasses. Steer carcasses also tended to have a greater rib primal weight (P = 0.08) and fore-quarter lean trim weight (P = 0.06) compared to heifer carcasses. Otherwise, the weight of all other primal/subprimal cuts from the fore-quarter, as well as fat trim and bone weights did not differ (P > 0.10) between steer and heifer carcasses. Tenderloin butt (NAMP#191) weight was greater (P ≤ 0.04) in steer carcasses compared to heifer carcasses; however, heifer carcasses had a greater weight of the bottom sirloin tri-tip (NAMP#185C; P ≤ 0.02) and flank steak (NAMP#193; P ≤ 0.02) compared to steer carcasses, with a tendency (P = 0.10) for a greater top sirloin butt cap weight in heifer carcasses as well. Heifer carcasses had a greater (P ≤ 0.01) weight of fat trim in the hind-quarter, in part due to a greater (P ≤ 0.02) weight of kidney fat, compared to steer carcasses, while steer carcasses had a greater ( P ≤ 0.04) weight of bone in the hind-quarter compared to heifer carcasses. Sex had no other effect (P > 0.11) on the weights of primal or subprimal cuts in the hind-quarter of the carcass. Other researchers (Bradley et al., 1966; Thrift et al., 1970; Tanner et al., 1970) have made carcass cutability comparisons between steer and heifer carcasses; however, steer carcass weights were greater (~25-30 kg) than heifer carcass weights. Cutability was estimated in the previously mentioned research using the 9-10-11th rib separation technique described by Hankins and Howe (1946) or percent BCTRC equation reported by Murphey et al. (1960). Bradley et al. (1966) reported a greater percentage of lean and a lesser fat percentage for steer carcasses compared to heifer carcasses, which are in agreement with the results of the present study. In disagreement, Bradley et al. (1966) reported a similar percentage of bone for steer carcasses compared to heifer carcasses,

71 whereas the results of the present study demonstrated a greater percentage of bone for steer carcasses compared to heifer carcasses. Likewise, Thrift et al. (1970) reported greater estimates for percent BCTRC of steer carcasses compared to heifer carcasses. However, Tanner et al. (1970) reported no differences in the estimation of percent BCTRC between steer and heifer carcasses, only for bull carcasses. With similar carcass weights between steer and heifer carcasses, Hedrick et al. (1969) reported a greater retail yield in experiment 1 (67.0 vs. 62.7%), but not experiment 2 (62.0 vs. 60.0%) for steer carcasses compared to heifer carcasses when performing an actual carcass cut-out. Similar to the results from our present study, steer carcasses from Hedrick et al. (1969) had a greater percentage of bone and a lesser percentage of fat compared to heifer carcasses. Warner-Bratzler shear force

Sire breed, sex, postmortem aging, and their interactions were evaluated for WBSF of ribeye steaks. The three-way interaction (P = 0.91) and two-way interactions (P > 0.15) between sire breed, sex, and postmortem aging period, and the main effect of sex (P = 0.79), did not affect the WBSF of crossbred Jersey ribeye steaks. Likewise, Hedrick et al. (1969) reported no difference in shear force between steers and heifers. Postmortem aging improved (P ≤ 0.01) tenderness of ribeye steaks from 7 to 14 d (2.96 vs. 2.46 kg), but significant tenderness was not gained past 14 d with additional aging to either 21 (2.33 kg; P = 0.21) or 28 (2.37 kg; P = 0.36) d postmortem (Figure 2). Steaks from 90.1% of the cattle in the present study would qualify to use the USDA AMS labeling claim “very tender” (< 3.9 kg; ASTM, 2011) after 7 d of postmortem aging, and 98.6% of ribeye steaks would qualify after 14 d of postmortem aging. The lack of improved tenderness from 14 to 21 or 28 d in the present study may be partially explained by results from Gruber et al. (2006), who reported that the USDA QG can affect the rate of improved tenderization during a 28-d postmortem aging period. A LM with a USDA QG in the upper two-thirds of Choice completes 94.7% of its 28-d max tenderness by d 14, while a LM with a USDA QG of Select will only complete 65.8% and 86.6% of its 28-d tenderness by d 14 and 21, respectively (Gruber et al., 2006).

Ribeye steaks from SimAngus- and Wagyu-sired (2.45 and 2.44 kg) cattle had a lesser WBSF value (P ≤ 0.01), and as a result were more tender compared to steaks from Angus-sired cattle (2.69 kg; Table 8). Radunz et al. (2009) did not report any differences between Wagyu- and Angus-sired steers for WBSF after 3 or 14 d of aging postmortem. Koch et al. (1976) reported Simmental- and Limousin-sired steers to have the greatest WBSF values when compared to Angus-, Hereford-, Jersey-, South Devon-, and Charolais-sired steers. In addition, Koch et al. (1976) and Ramsey et al. (1963) reported Jersey-sired cattle to produce the most tender steaks when compared to the other sire breeds investigated. However, Koohmaraie et al. (1995) reports there is more variation in tenderness within breed, depending on sire selection, than the variation in tenderness between breeds. Overall, crossbreeding with Jersey genetics resulted in the production of a very tender beef product. Fatty acid composition

There were no sire breed × sex interactions for the fatty acid composition of the LM from crossbred Jersey cattle. Angus-sired cattle had the greatest (P ≤ 0.01) percentage of total lipid deposited in the LM when compared to SimAngus- and Wagyu- sired cattle (Table 10). The LM from Wagyu-sired cattle had greater percentages of myristic (14:0; P ≤ 0.03) and palmitoleic (16:1; P ≤ 0.03) acid compared to LM from Angus- and SimAngus-sired cattle. The LM from Angus-sired cattle had a greater (P ≤ 0.01) percentage of oleic acid (18:1cis9) compared to the LM from Wagyu-sired cattle, but the LM from Wagyu-sired cattle had a greater (P ≤ 0.02) percentage of other 18:1 cis fatty acids compared to the LM from SimAngus-sired cattle. SimAngus-sired cattle tended (P = 0.08) to have a greater percentage of linolenic acid (18:3) in the LM compared to the LM from Angus-sired cattle, while Wagyu-sired cattle tended to have a greater (P = 0.09) percentage of polyunsaturated fatty acids (PUFA) in the LM compared to the LM from Angus-sired cattle. The proportion of oleic acid, linoleic acid, monounsaturated fatty acid (MUFA), PUFA, and PUFA:SFA ratio demonstrated significant (P ≤ 0.05) linear relationships with the percentage of total lipid in the LM. Standardizing fatty acid composition to a similar percentage of lipid via covariate

73 analysis did not result in any significant sire breed differences, with only a tendency (P = 0.08) for a greater percentage of oleic acid for Angus-sired cattle compared to Wagyu- sired cattle. Therefore, the inherent lipid level is important for describing the fatty acid composition in the LM of cattle. Pitchford et al. (2002) reported Jersey-, Wagyu-, and Angus-sired cattle as having the greatest percentage of intramuscular fat when compared to cattle sired by Hereford, South Devon, Limousin, and Belgian Blue bulls. Additionally, Pitchford et al. (2002) reported Jersey- and Wagyu-sired cattle to have a greater desaturase index for converting stearic acid into oleic acid, resulting in a greater percentage of MUFA, which was responsible for their lower melting point and softer fat compared to fat from cattle of the different sire breeds investigated. When comparing the fatty acid composition of Angus- and Wagyu-sired steers offered a diet consisting of alfalfa hay and barley, Xie et al. (1996) reported a greater percentage of 14:0, 14:1, 16:0, 16:1, but a lesser percentage of 18:0, 18:2, PUFA, and PUFA:SFA in the LM of Wagyu-sired steers compared to Angus- sired steers. Furthermore, Xie et al. (1996) reported negative relationships of 18:0, 18:2, and PUFA with the percentage of lipid in the LM. Bures et al. (2006) reported greater percentages of 18:3 and SFA in the LM of Angus bulls compared to Simmental bulls, while the LM of Simmental bulls had greater desaturase indices for converting palmitic acid to palmitoleic acid and stearic acid to oleic acid compared to Charolais bulls. The LM of Angus and Simmental bulls also had greater percentages of 18:1cis9 and MUFA compared to the LM of Charolais bulls. Overall, the differences in fatty acid composition due to breed appear to be relatively small compared to other factors such as dietary management and carcass fatness. Steers and heifers deposited a similar (P = 0.17) percentage of total lipid in the LM (8.13 vs. 9.08, respectively). The LM from heifers tended (P = 0.07) to have a greater percentage of oleic acid, greater (P ≤ 0.02) percentages of other 18:1 cis fatty acids, MUFA, MUFA:SFA, but a lesser percentage of SFA compared to the LM from steers. Standardizing fatty acid composition to a similar total lipid content, continued to demonstrate an effect of sex (P ≤ 0.01) on MUFA percentage, but no longer for oleic acid

74 percentage (P = 0.14). Similarly, Kazala et al. (1999) reported the fatty acid composition of the LM from crossbred Wagyu steers and heifers and found heifers have a greater desaturase index for converting stearic acid into oleic acid, a greater percentage of oleic acid, and MUFA:SFA, and a lesser percentage of 16:0 compared to steers.

APPLICATIONS

The objectives were to investigate the ability of different terminal sire breeds, when mated with Jersey cows, to add value to male Jersey offspring. The value of male offspring can be realized at different places within the beef market chain: sale of calf, sale of fed cattle on a live or carcass grid basis, or as boxed beef. Angus- and SimAngus- sired cattle had increased feedlot value because of a greater ADG, off-test BW, and fewer DOF compared to Wagyu-sired cattle. When selling on a grid basis or as boxed beef, Angus-sired cattle had increased value because of greater USDA QG compared to SimAngus- and Wagyu-sired cattle. Additional value may be available to SimAngus- and Wagyu-sired cattle in niche markets as they produced steaks that were more tender compared to steaks from Angus-sired cattle. Sire selection criteria remains very important within and across sire breeds.

LITERATURE CITED

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Table 6. Composition (%) of diets offered during the experiment on a DM basis Finishing Finishing Item Receiving Growing Corn Silage Soy Hulls Ingredient ------DM basis ------Whole shelled corn 15.00 20.00 50.00 55.00 DDGS 15.00 20.00 20.00 15.00 Soy hulls 0.00 0.00 0.00 20.00 Corn silage 60.00 50.00 20.00 0.00 Supplement 10.00 10.00 10.00 10.00 Ground corn 2.26 4.07 5.77 5.77 Urea 0.50 0.50 0.50 0.50 Soybean meal 5.45 2.00 1.00 1.00 Limestone 0.72 1.80 1.10 1.10 Dicalcium Phosphate 0.11 0.00 0.00 0.00 White salt 0.16 0.50 0.50 0.50 Vit. A, 30,000 IU/g 0.01 0.01 0.01 0.01 Vit. D, 3,000 IU/g 0.01 0.01 0.01 0.01 Vit. E, 44 IU/g 0.02 0.02 0.02 0.02 Calcium Sulfate 0.40 0.70 0.70 0.70 Selenium, 201 ppm 0.02 0.04 0.04 0.04 Rumensin 90 1 0.01 0.02 0.02 0.02 Potassium Chloride 0.30 0.30 0.30 0.30 Cobalt Carbonate 0.00 0.01 0.01 0.01 Copper Sulfate 0.01 0.02 0.02 0.02 Zinc Sulfate 0.02 0.01 0.01 0.01 Magnesium Sulfate 0.01 0.00 0.00 0.00

Table 7. Effect of terminal sire breed on the feedlot performance of crossbred Jersey steers and heifers adjusted to a similar initial BW (203 kg) Sire breed Sex Angus SimAngus Wagyu Heifer Steer Item (n = 20) (n = 29) (n = 22) SEM 1 (n = 37) (n = 34) SEM 1 Initial BW, kg 219 d 201 e 189 e 6.06 200 206 4.71 Age at receiving, d 23 227 222 225 3.76 229 221 3.02 WDA at entry, kg/d 234 0.89 0.91 0.90 0.014 0.88 0.91 0.012

Average daily gain, kg/d 1.01 d 1.01 d 0.89 e 0.026 0.91 z 1.03 y 0.020 Daily DMI, kg/d 2 7.37 d 7.08 d 6.47 e 0.130 6.74 z 7.21 y 0.097 Total DMI, kg 2291 2275 2194 105 2218 2289 101 Gain:feed, kg/kg 2 0.137 0.132 0.133 0.0047 0.130 x 0.138 w 0.0040

Days on feed, d 2 311 e 322 e 345 d 13.0 332 y 320 z 12.6 e e d y z 82 Age at harvest, d 537 552 573 13.3 562 546 12.7 Off-test weight, kg 2 522 ab 527 a 506 b 9.20 504 z 533 y 7.93 a-c Sire breed lsmean estimates within a row with a different superscript differ (P ≤ 0.05). d-f Sire breed lsmean estimates within a row with a different superscript differ (P ≤ 0.01). w,x Sex lsmean estimates within a row with a different superscript differ (P ≤ 0.05). y,z Sex lsmean estimates within a row with a different superscript differ (P ≤ 0.01). 1 The reported standard error of the mean is the greatest between the sire breed and sex treatment levels. 2 Variables were standardized to a common weight (203 kg) using initial weight as a linear covariate. 3 Age at receiving (P ≤ 0.05) and WDA (P ≤ 0.01) had a sire breed × sex interaction, refer to the first paragraph of the feedlot performance results for more details. 4 WDA (weight per day of age) = initial weight / age at receiving.

Table 8. Effect of terminal sire breed on carcass characteristics of crossbred Jersey steers and heifers adjusted to a similar HCW (319 kg) Sire Breed Sex Angus SimAngus Wagyu Heifer Steer Item (n = 20) (n = 29) (n = 22) SEM 1 (n = 37) (n = 34) SEM 1 Final BW, kg 510 d 510 d 485 e 6.48 487 z 516 y 5.13 HCW, kg 327 d 324 d 306 e 4.49 308 z 330 y 3.50 Dressing percent, % 64.11 63.27 63.12 0.311 63.21 63.78 0.243 Fat thickness, cm 2 1.47 a 1.17 b 1.11 b 0.100 1.36 y 1.14 z 0.087 LM area, cm2 76.4 75.2 74.1 4.31 75.4 75.1 4.20 Kidney fat, % 2 5.79 b 6.79 a 7.21 a 0.356 6.99 y 6.20 z 0.336 Calculated Yield grade 3 3.96 4.06 4.03 0.254 4.17 3.87 0.246 Calculated BCTRC, % 24 47.61 47.38 47.44 0.586 47.13 47.83 0.567 Marbling score 25 800 a 677 b 690 b 30.2 738 706 23.5

Quality grade 6 13.52 a 12.26 b 12.38 b 0.299 12.88 12.56 0.233 8

Lean color L* 46.2 a 43.3 b 44.1 b 0.503 44.0 x 45.1 w 0.392 a* 25.5 b 26.6 a 26.5 a 0.533 26.1 26.3 0.502 2 b* 9.6 9.6 10.0 0.592 9.3 10.2 0.462 Fat color L* 72.9 73.7 72.1 0.737 73.0 72.9 0.634 a* 14.7 12.7 13.7 0.720 13.7 13.7 0.562 b* 20.9 a 19.1 b 18.5 b 0.408 19.8 19.2 0.318

Continued

Table 8. Continued

WBSF, kg 2.69 d 2.45 e 2.44 e 0.065 2.54 2.52 0.051 a-c Sire breed lsmean estimates within a row with a different superscript differ (P ≤ 0.05). d-f Sire breed lsmean estimates within a row with a different superscript differ (P ≤ 0.01). w,x Sex lsmean estimates within a row with a different superscript differ (P ≤ 0.05). y,z Sex lsmean estimates within a row with a different superscript differ (P ≤ 0.01). 1 The reported standard error of the mean is the greatest between the sire breed and sex treatment levels. 2 Variables were standardized to a common weight (319 kg) using HCW as a linear covariate. 3 Yield grade = 2.5 + (2.5 × (fat thickness / 2.54)) + (0.2 × kidney, pelvic, heart fat) + (0.0038 × (HCW / 0.453592)) - (0.32 × (LM area / 6.4516)). 4 BCTRC (Boneless closely trimmed retail cuts) = 51.34 - (2.28 × (fat thickness)) - (0.462 × %kidney fat) - (0.02 × (HCW)) + (0.1147 × (LM area)). 5 Marbling score is based on a numeric scale: 500-599 = modest, 600-699 = moderate, 700-799 = slightly abundant. 6

8 Quality grade is based on a numeric scale: 11 = average choice, 12 = high choice, 13 = low prime. 4

3.4 a 3.2

3.0

2.8 b b b

2.6 WBSF, kg WBSF, 2.4

2.2

2.0 7 14 21 28

Postmortem aging, d

8 5

Figure 2. Effect of postmortem aging period on the Warner-Bratzler shear force of the LM from crossbred Jersey cattle. Postmortem aging lsmean estimates with a different superscript differ (P ≤ 0.01).

Table 9. Effect of sire breed on the distribution of carcass weight into retail cuts from crossbred Jersey steers and heifers adjusted to a similar chilled carcass side weight (154 kg) Sire Breed Sex Angus SimAngus Wagyu Heifer Steer Item, kg (n = 20) (n = 29) (n = 22) SEM 1 (n = 37) (n = 34) SEM 1 Side weight, kg 158.2 d 156.2 d 148.7 e 2.14 148.8 z 160.0 y 1.67 Total red meat, kg 23 84.6 86.8 85.4 2.35 83.8 x 87.4 w 2.29 Retail yield, % 4 34.64 35.39 35.35 0.629 34.89 35.36 0.578 Total red meat yield, % 23 55.16 56.29 55.69 1.417 54.99 x 56.44 w 1.374 Fat yield, % 2 24.83 23.45 24.04 1.329 25.48 w 22.74 x 1.620 Bone yield, % 19.21 19.39 20.16 0.650 18.91 x 20.26 w 0.567 Chuck, kg 2 12.86 13.39 12.93 0.577 12.57 x 13.55 w 0.544 Shoulder clod, kg 2 3.85 4.12 3.75 0.440 3.70 4.11 0.428 Top blade, kg 2 1.40 1.51 1.40 0.076 1.33 x 1.55 w 0.061 Clod teres major, kg 0.39 0.40 0.44 0.053 0.39 0.43 0.048 Chuck tender, kg 2 0.95 0.93 0.96 0.054 0.93 0.97 0.051

8 Boneless chuck roll – 6 2 6.27 6.46 6.34 0.165 6.19 6.52 0.133 5.08×5.08 cm tail, kg Brisket Brisket, kg 2 5.55 d 4.76 e 4.47 e 0.282 4.80 5.06 0.265 Rib, kg 2 6.83 6.42 6.43 0.198 6.37 6.76 0.155 Ribeye roll, kg 2 5.05 4.95 4.93 0.120 4.99 4.96 0.098 Back-ribs, kg 1.66 1.56 1.62 0.079 1.58 1.65 0.070 Plate Skirt steak-inside, kg 0.68 a 0.65 a 0.52 b 0.085 0.59 0.63 0.079 Skirt steak-outside, kg 2 0.40 0.45 0.36 0.029 0.42 0.39 0.029

Continued

Table 9. Continued

Loin, kg 2 10.90 b 11.36 ab 11.73 a 0.204 11.43 11.23 0.164 Striploin - 2.54 cm tail, kg 2 4.45 4.46 4.67 0.203 4.62 4.43 0.195 Tenderloin tail, kg 0.85 0.92 0.91 0.083 0.87 0.92 0.081 Tenderloin butt, kg 0.96 1.01 0.98 0.038 0.94 x 1.03 w 0.031 Top sirloin butt (boneless), kg 2 2.70 e 2.96 d 3.14 d 0.094 2.99 2.88 0.076 Top sirloin butt cap, kg 2 0.69 0.78 0.81 0.048 0.81 0.72 0.042 Bottom sirloin ball tip, kg 0.56 0.53 0.44 0.169 0.45 0.57 0.169 Bottom sirloin tri-tip, kg 2 0.75 0.78 0.84 0.059 0.84 w 0.74 x 0.056

Flank Flank steak, kg 2 0.67 0.71 0.67 0.021 0.72 w 0.65 x 0.017

Round, kg 2 15.61 e 16.89 d 17.35 d 0.310 16.85 16.38 0.262 2 b a a

8 Knuckle (peeled), kg 3.48 3.83 3.93 0.124 3.76 3.74 0.102

7 2 e e d Inside round (boneless), kg 6.63 6.97 7.56 0.186 7.10 7.00 0.158 Bottom round eye, kg 2 1.59 e 1.71 d 1.56 e 0.082 1.65 1.59 0.079 Bottom round flat, kg 2 4.13 4.37 4.30 0.148 4.34 4.19 0.119

Continued

Table 9. Continued

Lean trim - fore, kg 2 19.71 b 21.65 a 21.03 ab 0.936 20.19 21.40 0.888 Lean trim - hind, kg 11.72 10.60 10.07 0.553 10.59 11.01 0.444 Total lean trim, kg 2 31.47 32.19 31.38 1.309 31.07 32.29 1.262

Fat trim - fore, kg 2 15.53 d 13.06 e 12.62 e 1.845 14.29 13.18 1.812 Fat trim - hind, kg 25 22.91 23.18 24.41 0.828 24.89 y 22.11 z 0.665 Kidney fat, kg 2 8.81 e 10.37 d 11.10 d 0.558 10.75 w 9.44 x 0.533 Total fat trim, kg 2 38.45 36.24 37.03 2.057 39.18 y 35.30 z 1.966

Bone - fore, kg 2 18.27 18.99 19.29 0.801 18.11 19.59 0.643 Bone - hind, kg 11.64 11.12 11.45 0.840 10.68 z 12.13 y 0.745 Total bone, kg 2 29.71 30.00 31.11 0.981 29.18 x 31.39 w 0.859 a-c Sire breed lsmean estimates within a row with a different superscript differ (P ≤ 0.05).

8 d-f

8 Sire breed lsmean estimates within a row with a different superscript differ (P ≤ 0.01). w,x Sex lsmean estimates within a row with a different superscript differ (P ≤ 0.05). y,z Sex lsmean estimates within a row with a different superscript differ (P ≤ 0.01). 1 The reported standard error of the mean is the greatest between the sire breed and sex treatment levels. 2 Variables were standardized to a common weight (154 kg) using chilled side carcass weight as a linear covariate. 3 Total red meat yield is the sum of the boneless closely trimmed retail cuts and lean trimmings. 4 Retail yield refers to boneless closely trimmed retail cuts. 5 Fat trim from the hind quarter includes the kidney fat.

Table 10. Effect of sire breed on the fatty acid composition of the LM from purebred and crossbred Jersey steers and heifers Sire Breed Sex Angus SimAngus Wagyu Heifer Steer Item, % SEM 1 SEM 1 (n = 20) (n = 29) (n = 22) (n = 37) (n = 34) Total lipid, % 10.42 d 7.68 e 7.73 e 0.611 9.09 8.13 0.475

14:0, % 3.46 b 3.45 b 3.82 a 0.134 3.51 3.64 0.114 14:1, % 1.19 1.14 1.15 0.067 1.16 1.16 0.052 16:0, % 26.97 26.80 27.01 0.328 26.66 27.20 0.256 16:1, % 4.33 b 4.83 b 5.62 a 0.480 5.06 4.80 0.429 18:0, % 10.99 11.08 10.48 0.375 10.61 11.09 0.333 18:1 trans, % 3.56 3.44 3.45 0.504 3.51 3.47 0.477 18:1 cis 9, % 40.76 d 39.47 de 38.42 e 0.538 40.09 39.01 0.432 18:1 cis others, % 2.60 ab 2.45 b 2.69 a 0.091 2.66 w 2.50 x 0.082 18:2, % 3.21 3.41 3.53 0.109 3.31 3.45 0.085 18:3, % 0.08 b 0.12 a 0.11 ab 0.021 0.10 0.11 0.020

SFA, % 41.31 41.32 41.27 0.497 40.73 x 41.87 w 0.402 MUFA, % 52.38 51.32 51.30 0.470 52.43 y 50.90 z 0.366 PUFA, % 3.29 3.52 3.64 0.110 3.41 3.56 0.086 MUFA:SFA 1.274 1.246 1.253 0.025 1.295 y 1.220 z 0.020 PUFA:SFA 0.080 0.085 0.089 0.003 0.085 0.085 0.002 Desaturase (14) 2 25.52 24.61 23.03 0.920 24.82 23.95 0.717 Desaturase (16) 2 13.96 b 15.12 ab 17.10 a 1.146 15.81 14.97 1.004 Desaturase (18) 2 78.68 78.06 78.62 0.698 79.09 y 77.82 z 0.640 a-c Sire breed lsmean estimates within a row with a different superscript differ (P ≤ 0.05). d-f Sire breed lsmean estimates within a row with a different superscript differ (P ≤ 0.01). w,x Sex lsmean estimates within a row with a different superscript differ (P ≤ 0.05). y,z Sex lsmean estimates within a row with a different superscript differ (P ≤ 0.01). 1 The reported standard error of the mean is the greatest between the sire breed and sex treatment levels. 2 Index of delta desaturase enzyme activity on the conversion of 14:0 to 14:1, 16:0 to 16:1, and 18:0 to 18:1 cis 9 [e.g. = 100 * (18:1 cis 9 / (18:0 + 18:1 cis 9))].

Chapter 5. Opportunities to improve the accuracy of the United States Department of Agriculture beef yield grade equation through precision agriculture

ABSTRACT

The USDA yield grade (YG) equation is used to predict the cutability of beef carcasses and provide accurate payment of cattle when sold on a grid pricing system. The current USDA YG equation was developed over 50 years ago with the use of different cattle than what currently represents the diverse U.S. beef cattle supply today. The objectives of this technical note are to demonstrate the inability of the current USDA YG equation to predict the cutability of a population of cattle that contribute to the current U.S. beef supply and to promote the adoption and use of precision agriculture technologies (camera grading and electronic animal identification) throughout the U.S. beef supply chain. Camera grading has improved the accuracy of determining beef carcass retail yield; however, the use of electronic animal identification would allow for information to be passed back and forth between the packer and cattle feeder and producer. Information such as sex, genetics, medical treatment history, diets consumed, and growth promotant administration could be used to create additional variables for a new augmented USDA YG equation. Herein, fabrication yields demonstrated a 5.6 USDA YG and 12.8% boneless closely trimmed retail cut (BCTRC) difference between actual and calculated values from Jersey influenced cattle. Evidence of such disparities between calculated and actual values warrants a reevaluation of the USDA YG for the prediction of beef carcass retail yield that will account for the large amount of variation in the prediction of beef carcass retail yield provided by the cattle in the U.S.

INTRODUCTION

In the United States, beef carcasses can be awarded a quality grade (QG) indicative of eating satisfaction and a yield grade (YG) indicative of the amount of saleable retail product received from the carcass (USDA, 2016). Carcass value is largely determined by hot carcass weight (HCW), but it can also be influenced by premiums and discounts received based on the predicted meat quality and retail yield. The beef grading system used in the United States allows packers to more accurately pay cattle producers and feeders based on the current, estimated value of their cattle. Premiums and discounts assigned to the price of beef act as the signals sent from the beef purchasing customers to the beef producer to indicate the demand for beef that meets the customer’s desired specifications. Research conducted by Murphey et al. (1960) was used to develop the current USDA YG equation used to estimate the percent boneless closely trimmed retail cuts (BCTRC) produced from the beef carcass. Predictor variables used to estimate the percent BCTRC retrieved from the beef carcass include HCW, back fat thickness (BFT), kidney, pelvic, and heart fat percentage (KPH), and longissimus muscle area (LMA). With the current USDA YG equation (percent BCTRC = -2.3* YG + 56.9), a change of one YG represents a 2.3% change in the percent of BCTRC retrieved from the carcass. Yield grades are awarded on a 1 to 5 scale, where a YG 1 carcass would be expected to produce greater than 52.3% BCTRC, while a YG 5 carcass would be expected to produce less than 45.4% BCTRC from the beef carcass. The current USDA YG equation has been used in the beef industry for over 50 years, with a “one size fits all” approach. Cattle in the U.S. were smaller framed at the time when Murphey et al. (1960) developed the USDA YG equation. However, the cattle population that currently contributes to the United States beef supply is quite diverse and is comprised of a variety of purebred and crossbred cattle breeds. Different cattle breeds or cattle-types were designed for different purposes or combination of purposes, such as beef production, draft, dairy production, environmental tolerance, among others. As a result, cattle in the U.S. can have extremely different growth curves that represent differences in birth

91 weight, rate of growth, and mature body weight (Owens et al., 1995). Cattle in the U.S. can vary widely in carcass composition, mostly due to differences in the location of carcass fat deposition (i.e. subcutaneous, intermuscular, and kidney fat). However, cattle with varying phenotypes and genotypes (i.e. beef-type vs. dairy-type) can also produce carcasses with vastly different muscle:bone ratios, which can contribute to differences in carcass composition. In the last two decades, advances in technology have been used to augment the application of USDA YG to beef carcasses with the use of camera grading systems in packing plants. The use of camera grading systems has improved the accuracy and repeatability in the determination of beef carcass USDA YG by reducing some of the human bias or human error in the USDA YG prediction (Hueth et al., 2007). In addition, other technological advances such as the adoption and use of electronic animal identification, allows for individual animal information to be passed back and forth through the supply chain between the packer and feedlot or producer. Information, such as sex, genetics, medical treatment history, diets consumed, growth promotant administration (i.e. exogenous hormone implants and β-agonists), carcass YG and QG, would all travel with the animal and resulting carcass as it progresses through the beef supply chain. This information could be incorporated into additional variables in an augmented yield grade equation for improved accuracy in predicting beef carcass cutability. The goal of this technical note is to demonstrate the inability of the USDA YG equation to predict beef carcass yield with the use of Jersey influenced cattle from a recent study conducted by Jaborek et al. (2019a, 2019b). A second goal of this technical note is to discuss the opportunities of adopting precision agriculture technologies to improve upon the accuracy and efficacy of the USDA YG equation and grading system.

MATERIALS AND METHODS

Animal procedures and husbandry practices were approved by the Institutional Animal Care and Use Committee (IACUC; protocol number 2015A00000093) of The

Ohio State University and followed the guidelines recommended in the Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching (FASS, 2010). Details regarding the animals used in this technical note have been reported previously by Jaborek et al. (2019a, 2019b). Briefly, purebred Jersey steers and crossbred Jersey steers and heifers were raised over the course of two years at the Ohio Agricultural Research and Development Center feedlot (Wooster, OH) where animals consumed similar feedlot diets. Cattle were not administered exogenous growth promotants (i.e. hormonal implants or β-adrenergic agonists) and were raised to obtain premium USDA QG to meet the requirements of a niche market that demands high quality, naturally raised beef. Cattle (n = 91) were harvested and fabricated at The Ohio State University meat laboratory (Columbus, OH) to determine the retail yield of each carcass. The current equations used to calculate the percent BCTRC (Murphey et al., 1960) and USDA YG (USDA, 2016) are shown in Table 11. Statistical analyses were performed using PROC MIXED in SAS (SAS Inst. Inc., Cary, NC). Missing kidney fat measurements from 9 cattle prevented their use for the analysis of YG, but not BCTRC. The equation term was included in the class statement to distinguish the calculated USDA data and actual Jersey data. The statistical model used was: Yijkl = μ + HCWi + BFTj + LMAk + KPHl + eijkl, where HCWi = hot carcass weight, BFTj = backfat thickness, LMAk = longissimus muscle area, KPHl = percent kidney, pelvic, and heart fat as continuous variables, and eijkl = random error. The calculated USDA data had minimal standard error as a result of being from predicted values. The estimate statement, 95% confidence intervals, and concordance correlation coefficient (CCC) were used to determine differences between the calculated USDA and actual Jersey data. The use of the backwards selection procedure in PROC REG selected only predictor variables with significant contributions (P ≤ 0.05) for the reduced equations, while the full models included all four predictor variables (HCW, BFT, LMA, KPH). All significant differences were established at P ≤ 0.05.

RESULTS & DISCUSSION

The USDA YG and BCTRC equations were created to gain a rapid prediction for the cutability of beef carcasses and, therefore, more accurately price beef carcasses. The YG of beef carcasses can be calculated from the USDA YG equation shown in Table 11. Likewise, the percent BCTRC can also be calculated with the USDA percent BCTRC equation (Murphey et al., 1960) shown in Table 11. When the USDA YG and USDA percent BCTRC equations are used to predict the cutability of the Jersey influenced cattle used in the present study, the data in the upper left corner of Figure 3 are created (calculated percent BCTRC vs. calculated YG). The relationship of the calculated USDA YG and calculated USDA percent BCTRC place the data points on the line where percent BCTRC = -2.3(YG) + 56.9. Representing a 2.3% change in BCTRC or retail yield for every one YG change. The USDA YG and BCTRC equations predict or calculate the Jersey influenced cattle used in the present study to receive a USDA YG ranging from 2.8 to 5.3 (푥̅ = 4.0) and produce carcasses ranging from 44.5% to 50.3% BCTRC (푥̅ = 47.6%). However, after fabricating these beef carcasses into BCTRC, as mentioned by Jaborek et al. (2019a, 2019b), the actual percentage of BCTRC was much lower than the calculated percentage of BCTRC, as shown in the lower left corner of Figure 3 (actual BCTRC vs. calculated YG). The USDA percent BCTRC equation overestimated (P ≤ 0.01) the actual percent BCTRC by 12.8%. The actual percentage of BCTRC of Jersey influenced cattle in the present study ranged from 29.9% to 41.7% BCTRC (푥̅ = 34.8%). Knowing the percent BCTRC was overestimated by the USDA percent BCTRC equation, we also knew the USDA YG equation would overestimate the cutability of the Jersey beef carcasses. In order to determine the actual YG of the Jersey influenced cattle used in the present study, the regression equation between the USDA YG and USDA percent BCTRC [YG = (percent BCTRC-56.9)/-2.3] needed to be rearranged. Data in the bottom right corner of Figure 3 were created using the actual percentage of BCTRC to determine the actual YG of the Jersey influenced cattle used in the present study. As a result, the actual USDA YG for the Jersey influenced cattle ranged from 6.6 to 11.7 (푥̅ = 9.6), with all cattle

94 receiving a YG outside the USDA’s one to five scale for YG. The difference (P ≤ 0.01) between the calculated USDA YG and actual YG was 5.6 USDA YG, which was a 140% increase in USDA YG! Concordance correlation coefficient analysis (CCC = 0.01 for YG and BCTRC) demonstrates the inability of the USDA YG and BCTRC equations to predict or calculate the actual YG and BCTRC of the Jersey influenced cattle used in the present study. Linear regression equations were developed to demonstrate the relationships between the calculated USDA data and the actual Jersey data for percent BCTRC and YG (Table 12). A perfect fit between the calculated USDA data and the actual Jersey data would produce an equation with a slope equal to one and a y-intercept equal to zero. However, for percent BCTRC and YG, the y-intercepts and slopes differed from one and zero, respectively. While these linear regressions may produce a BCTRC and YG estimate with greater precision than the USDA YG alone, the adjusted R2 values (Adj. R2 = 0.21) indicate that these linear regression equations do not accurately predict the percent BCTRC and USDA YG of Jersey influenced cattle. Multiple linear regressions for Jersey YG (Adj. R2 = 0.02) and percent BCTRC (Adj. R2 = 0.03) equations were created with the same predictor variables (HCW, BFT, KPH, LMA) as the current USDA YG and percent BCTRC equations (Table 11). The 95% confidence intervals demonstrate significant differences for the intercept, BFT, and LMA parameter estimates, and the intercept, BFT, and KPH between the USDA and Jersey YG and percent BCTRC equations, respectively. Reduced Jersey models for YG (Adj. R2 = 0.06) and percent BCTRC (Adj. R2 = 0.18) were created (Table 13) when percent KF (P = 0.18) and HCW (P = 0.09) were dropped from the full Jersey YG and percent BCTRC models. Based on the adjusted R2 values from these multiple linear regression equations, the use of HCW, BFT, KPH, LMA as predictor variables in the full Jersey model, or only BFT and LMA in the reduced Jersey model, do not accurately predict the BCTRC and USDA YG of Jersey influenced cattle. Similarly, Crouse et al. (1975) reported HCW was not a great predictor of carcass cutability. Crouse et al. (1975) reported that HCW was a better predictor within breed groups than for the entire

95 population containing multiple cattle breeds. Data presented by Crouse et al. (1975) also demonstrated that HCW was a better predictor for British and Continental cattle breeds compared with Jersey influenced cattle. Interestingly, KF percent was the first variable removed from the full models (Table 11) in the present study, even though Murphey et al. (1960) and Crouse et al. (1975) reported it was a significant contributor to predicting the percent BCTRC of beef carcasses. The lack of fit from the models shown in Tables 11 and 13 demonstrate the inability of the USDA YG equation to accurately predict beef carcass cutability with only HCW, BFT, KPH, LMA as the predictor variables in the equation. Additional variables or coefficients are needed to improve the accuracy the USDA YG equation’s ability to predict percent BCTRC of the cattle contributing to the U.S. beef supply. As previously mentioned, the USDA YG equation was developed over 50 years ago to fit the cattle in the U.S. beef industry at that time. However, the same USDA YG equation is being erroneously used 50 years later with a “one size fits all” approach. Over the past 50 years, the beef industry has evolved, and changes in genetics and the use of growth promoting technologies have contributed to the variation of beef carcass retail yield. Though a by-product of the dairy industry, a greater number of purebred dairy steers and dairy crossbred cattle are being raised for beef production. According to the 2016 National Beef Quality Audit, 16.3% of the fed cattle harvested were dairy-type (Boykin et al., 2017). This manuscript has demonstrated the inability of the USDA YG equation to accurately predict the cutability of the Jersey influenced cattle (purebred Jersey steers, Angus sired, SimAngus sired, and Red Wagyu sired steers and heifers) used in the present study. Koch and Dikeman (1977) reported implanted Jersey influenced (Jersey×Hereford and Jersey×Angus) steers to have a total lean yield (retail yield + lean trim), fat trim yield, and bone yield of 64.2 to 67.3%, 20.0 to 24.3%, and 11.4 to 12.7%, respectively for three different harvest groups. In comparison, Jersey influenced cattle from the present study produced a total lean yield, fat trim yield, and bone yield of 55.3%, 24.1%, and 20.0%, respectively. The noticeable difference between the carcass composition of the Jersey influenced cattle in the present study and of the Koch and

Dikeman (1977) study is the percentage of total lean yield (e.g. muscle) and bone yield. A lesser muscle to bone ratio for cattle used in the present study may be due to the genetic selection of Jersey cattle for dairy type and milk production traits compared to carcass retail value over the past 40 years. Likewise, Lawrence et al. (2010) reported the USDA YG equation was not able to accurately predict the cutability of implanted calf-fed Holstein steers (Adj. R2 = 0.01). The Holstein steer carcasses produced a total lean yield, fat trim yield, and bone yield of 68.2%, 10.5%, and 21.2%, respectively (Lawrence et al., 2010). Lawrence et al. (2010) believe a predictor of bone quantity is needed in the USDA YG equation to improve the prediction of calf-fed Holstein carcass cutability. In addition to dairy-type beef carcasses, Lawrence et al. (2010) also reported the ability of USDA YG equation to predict the beef retail yield of the control beef-type steers used in their study was poor (Adj. R2 = 0.38). Growth promoting technologies (i.e. implants and β-adrenergic agonists) are commonly used to promote efficient body weight gains and increase muscle mass of feedlot cattle. While exogenous hormone implants were approved for use before the USDA YG equation was developed, β-adrenergic agonists have only been approved for use in the last 20 years. In comparison to carcasses from non-implanted steers, Foutz et al. (1997) reported a greater percentage of boneless chuck and striploin from carcasses of implanted steers. Some of the additional weight in the chuck of implanted steers may have been due to a greater splenius muscle weight, as steers administered a trenbolone acetate implant had a greater splenius to chuck ratio (Foutz et al., 1997). When comparing β-agonist supplemented and non-supplemented steer carcasses, Hilton et al. (2010) reported the majority of the subprimal cuts in the round and loin primals, plus the brisket and ribeye roll, contributed a greater percentage of weight in the carcass from steers supplemented with the β-agonist (Zilmax). Therefore, the use of growth promoting technologies, such as implants and β- agonists, can alter the distribution of muscle weight within the carcass of cattle. The use of LMA alone, in the USDA YG equation is unable to account for alterations in the distribution of muscle weight in the carcass. This claim is further supported by Lawrence et al. (2010), which reported a greater total lean yield

97 from carcasses of steers (beef-type and Holstein steers) supplemented with Zilmax compared to carcasses from non-supplemented steers when compared at a similar calculated USDA YG. As reported by Jaborek et al. (2019a, 2019b), carcass fat deposition can vary by breed, with Jersey cattle having a greater percentage of kidney fat and a lesser backfat thickness compared with Angus cattle, for example. The USDA YG equation considers subcutaneous and kidney fat measurements for the prediction of YG. However, the estimation of KPH fat percentage introduces subjectivity and error into the estimation of carcass retail yield. In the studies conducted by Jaborek et al. (2019a, 2019b) KPH percentage was estimated and kidney fat was objectively weighed to control for human error. An experienced carcass grader estimated a mean KPH fat percentage of 2.24% (SD = 0.469) for the Jersey influenced cattle used in the present study. However, the actual kidney fat weight contributed 6.84% (SD = 1.351) of the carcass weight for the Jersey influenced cattle used in the present study. The objective kidney fat measurement was three times greater and resulted in nearly an entire (0.9) YG difference compared to the subjective KPH percentage measurement. Farrow et al. (2009) reported that an actual measure of KPH increased the ability to predict beef carcass retail yield (Adj. R2 = 0.63) compared to using an estimated KPH value or when excluding KPH as a predictor variable in the YG equation (Adj. R2 = 0.57). Therefore, if KPH percentage is to be used as a predictor variable in the USDA YG equation, it should be as the actual kidney fat percentage to improve the accuracy of the prediction and eliminate human error. In the packing plant, USDA graders are under immense pressure because of the time constraints allowed to assign USDA grades. Adopting the use of precision agriculture technologies, such as camera grading, can augments the application of predicting the USDA YG (Hueth et al., 2007) and QG (Jang et al., 2017) of beef carcasses by eliminating grader bias. Cannell et al. (1999, 2002) reported that camera grading accounted for similar amounts of variation in predicting beef carcass retail yield as an expert off-line grader, which increased the amount of variation accounted for by 17 to 25% compared to on-line graders. Additionally, the use of camera grading in the

98 packing plant can be used for the development of a new and improved USDA YG equation. McEvers et al. (2012) used camera grading technology to develop new predictor variables at the 12th and 13th rib separation to improve the accuracy of predicting beef carcass retail yield. Newly developed equations by McEvers et al. (2012) were able account for significantly more variation in predicting beef carcass retail yield when compared with the current USDA YG equation (Adj. R2 = 0.62 vs. 0.39, respectively). McEvers et al. (2012) were also able to incorporate a coefficient for Zilmax treatment in their study to enhance the accuracy of the YG equation. The additional use of another precision agricultural technology in the beef industry, electronic animal identification, could allow for the sharing of information between the producer, cattle feeder, and packer. Similar to accounting for β-agonist supplementation in the YG equation model of McEvers et al. (2012), additional variables such as sex, genetics, medical treatment history, diets consumed, growth promotant administration (i.e. exogenous hormone implants and β-agonists), carcass YG and QG, would all travel with the animal and resulting carcass as it progresses through the beef supply chain. Not only would this enhance the efficacy of the USDA yield grade in predicting cutability and true value of beef carcasses, but it would also provide more accurate information for the supply chain and stimulate additional opportunities for production-level management practices and technology transfer to enhance production efficiencies and sustainability. Implications

In conclusion, we have reported and referenced additional supporting data to present the lack of accuracy the current USDA YG equation provides in predicting beef carcass retail yield for cattle that contribute to the current U.S. beef supply. Herein, we propose that the beef industry should capitalize on the opportunity to incorporate precision agriculture into the USDA beef grading system. The effective incorporation of precision agriculture technologies would allow for the creation of an augmented USDA YG equation and animal traceability; where individual animal data could be collected and shared throughout the beef supply chain between the packer and producer.

LITERATURE CITED

Cannell, R. C., J. D. Tatum, K. E. Belk, J. W. Wise, R. P. Clayton, and G. C. Smith. 1999. Dual-component video image analysis system (VIASCAN) as a predictor of beef carcass red meat yield percentage and for augmenting application of USDA yield grades. J. Anim. Sci., 77: 2942-2950. Cannell, R. C., K. E. Belk, J. D. Tatum, J. W. Wise, P. L. Chapman, J. A. Scanga, and G. C. Smith. 2002. Online evaluation of a commercial video image analysis system (Computer Vision System) to predict beef carcass red meat yield and for augmenting the assignment of USDA yield grades. J. Anim. Sci., 80: 1195-1201. Crouse, J. D., M. E. Dikeman, R. M. Koch, C. E. Murphey. 1975. Evaluation of traits in the USDA yield grade equation for predicting beef carcass cutability in breed groups differing in growth and fattening characteristics. J. Anim. Sci., 41: 548- 553. Farrow, R. L., G. H. Loneragan, J. W. Pauli, and T. E. Lawrence. 2009. An exploratory observational study to develop an improved method for quantifying beef carcass salable meat yield. Meat Sci., 82: 143-150. Foutz, C. P., H. G. Dolezal, T. L. Gardner, D. R. Gill, J. L. Hensley, and J. B. Morgan. 1997. Anabolic implant effects on steer performance, carcass traits, subprimal yields, and longissimus muscle properties. J. Anim. Sci., 75: 1256–1265. Hilton, G. G., A. J. Garmyn, T. E. Lawrence, M. F. Miller, J. C. Brooks, T. H. Montgomery, D. B. Griffin, D. L. VanOverbeke, N. A. Elam, W. T. Nichols, M. N. Streeter, J. P. Hutcheson, D. M. Allen, and D. A. Yates. 2010. Effect of zilpaterol hydrochloride supplementation on cutability and subprimal yield of beef steer carcasses. J. Anim. Sci., 88: 1817–1822. Hueth, B., P. Marcoul, and J. Lawrence. 2007. Grader bias in cattle markets? Evidence from Iowa. Amer. J. Agr. Econ., 89: 890-903. Jaborek, J. R., H. N. Zerby, S. J. Moeller, F. L. Fluharty, and A. E. Relling. 2019a. Evaluation of feedlot performance, carcass characteristics, carcass retail cut

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distribution, Warner-Bratzler shear force, and fatty acid composition of purebred Jersey and crossbred Jersey steers. Trans. Anim. Sci., 3: 1475-1491. Jaborek, J. R., H. N. Zerby, S. J. Moeller, F. L. Fluharty, and A. E. Relling. 2019b. Evaluation of feedlot performance, carcass characteristics, carcass retail cut distribution, Warner-Bratzler shear force, and fatty acid composition of crossbred Jersey steers and heifers. Appl. Anim. Sci. Jang, J.W., A. Ishdorj, D. P. Anderson, T. Purevjav, and G. Dahlke. 2017. Exploring the existence of grader bias in beef grading. J. Agr. Appl. Econ., 49: 467-489. Koch, R. M., and M. E. Dikeman. 1977. Characterization of biological types of cattle. V. Carcass wholesale cut composition. J. Anim. Sci., 45: 30-42. Lawrence, T. E., N. A. Elam, M. F. Miller, J. C. Brooks, G. G. Hilton, D. L. VanOverbeke, F. K. McKeith, J. Killefer, T. H. Montgomery, D. M. Allen, D. B. Griffin, R. J. Delmore, W. T. Nichols, M. N. Streeter, D. A. Yates, and J. P. Hutcheson. 2010. Predicting red meat yields in carcasses from beef-type and calf-fed Holstein steers using the United States Department of Agriculture calculated yield grade. J. Anim. Sci., 88: 2139-2143. McEvers, T. J., J. P. Hutcheson, and T. E. Lawrence. 2012. Quantification of saleable meat yield using objective measurements captured by video image analysis technology. J. Anim. Sci., 90: 3294-3300. Murphey, C. E., D. K. Hallett, W. E. Tyler, J. C. Pierce Jr. 1960. Estimating yields of retail cuts from beef carcasses. J. Anim. Sci., 19 (Suppl 1): 1240. Owens, F. N., D. R. Gill, D. S. Secrist, S. W. Coleman. 1995. Review of some aspects of growth and development of feedlot cattle. J. Anim. Sci., 73: 3152-3172. USDA. 2016. United States Standards for Grades of Carcass Beef. USDA, Washington, DC.

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55.0

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45.0

42.5

40.0

BCTRC, % BCTRC, 37.5

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25.0 1 2 3 4 5 6 7 8 9 10 11 12 USDA YG

Calc. BCTRC vs. Calc. YG Actual BCTRC vs. Calc. YG Actual BCTRC vs. Actual YG

Figure 3. Three relationships between percent boneless closely trimmed retail cuts (BCTRC) and USDA yield grade (YG) of purebred and crossbred Jersey cattle. The relationship between the calculated percent BCTRC and calculated USDA YG (●) is plotted in the upper left corner and follows the relationship Y = -2.3x + 56.9. The relationship between the actual percent BCTRC and calculated USDA YG (○) is plotted in the bottom left corner and follows the relationship Y = -1.29x + 39.6 (R2 = 0.22). The relationship between the actual percent BCTRC and actual USDA YG (▲) is plotted in the bottom right corner and follows the relationship Y = -2.3x + 56.9.

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Table 11. Comparison between current USDA regression equations for boneless closely trimmed retail cuts and yield grade and newly proposed regression equations for Jersey influenced cattle USDA Jersey 95% Confidence Interval Parameter 1 Estimate Estimate SE Lower Upper CCC 2 %BCTRC 0.0108 Intercept 51.34 34.68 2.734 29.231 40.121 HCW -0.0210 -0.0119 0.007 -0.026 0.002 BFT -2.28 -1.01 0.427 -1.858 -0.158 LMA 0.115 0.081 0.024 0.033 0.129 KPH 0.462 -0.192 0.141 -0.472 0.088

YG 0.0108 Intercept 2.50 9.66 1.188 7.296 12.029 HCW 0.0084 0.0052 0.003 -0.001 0.011 BFT 0.99 0.54 0.186 0.069 0.808 LMA 0.050 -0.035 0.010 -0.056 -0.014 KPH 0.200 0.083 0.061 -0.038 0.205 1 Percent boneless closely trimmed retail cuts (%BCTRC), yield grade (YG), hot carcass weight (HCW), backfat thickness (BFT), longissimus muscle area (LMA), percent kidney, pelvic, and heart fat (KPH). 2 Concordance correlation coefficient (CCC).

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Table 12. Linear regression equation for the prediction of percent boneless closely trimmed retail cuts and yield grade of Jersey influenced cattle from the USDA percent boneless closely trimmed retail cuts and yield grade. Parameter Estimate SE P-value Adj. R2 Root MSE 1 Jersey %BCTRC

Intercept (β0) 8.153 5.612 0.1502 0.21 1.411 USDA %BCTRC (β1) 0.554 0.118 0.0003

Jersey YG

Intercept (β0) 7.509 0.473 <0.0001 0.21 0.613 USDA YG (β1) 0.560 0.119 0.0004 1 Root Mean Square Error

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Table 13. Reduced equations of newly proposed boneless closely trimmed retail cut and yield grade regressions for Jersey influenced cattle Parameter 1 Estimate SE P-value Jersey %BCTRC Intercept 29.679 1.458 <0.0001 HCW ------0.0888 BFT -0.983 0.419 0.0216 LMA 0.080 0.020 0.0002 KPH ------0.1768

Jersey YG Intercept 11.835 0.634 <0.0001 HCW ------0.0888 BFT 0.428 0.182 0.0215 LMA -0.349 0.009 0.0002 KPH ------0.1765 1 Boneless closely trimmed retail cuts (BCTRC), yield grade (YG), hot carcass weight (HCW), backfat thickness (BFT), longissimus muscle area (LMA), percent kidney, pelvic, heart fat (KPH).

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Chapter 6. Comparison of feedlot performance, carcass characteristics, and fatty acid composition of Angus- and Wagyu-sired cattle when raised to a similar age or body weight

ABSTRACT

The Wagyu cattle breed is becoming increasingly popular in the United States due to their ability to deposit marbling and produce high quality beef. The present study compares the feedlot performance, carcass characteristics, and fatty acid composition of the Wagyu breed to the already popular Angus breed at a similar age and days on feed (DOF) endpoint or similar body weight (BW) endpoint. Angus steers (T1) were compared with cattle from two different Wagyu sires, Fukutsuru and Yasufuku, selected for growth or marbling, to be compared at a similar DOF (T2 and T3) or BW (T4 and T5). At a similar age and DOF, T1 cattle had a greater (P ≤ 0.01) off-test BW and average daily gain (ADG; P ≤ 0.04) compared with T3 cattle, while having a greater dry matter intake (DMI; P ≤ 0.01) compared with T2 and T3 cattle. Angus steers had a greater HCW (P ≤ 0.02), and a lesser percent KPH (P ≤ 0.01) compared with Wagyu- sired cattle. Yasufuku-sired cattle (T3) had a greater USDA QG (P ≤ 0.04), and marbling score at the 12th (P ≤ 0.04) and 6th rib (P ≤ 0.06) compared with T1 cattle. Yasufuku- sired cattle (T3) had a greater percentage of total lipid (P ≤ 0.01) and PUFA (P ≤ 0.01) in the Longissimus muscle compared with T1 and T2 cattle at a similar age and DOF endpoint. At similar BW endpoint, T1 cattle needed fewer (P ≤ 0.01) DOF, total feed (P ≤ 0.01), had a greater ADG (P ≤ 0.01), and feed efficiency (P ≤ 0.02) compared with T4 and T5 cattle. At a similar BW or HCW (P ≤ 0.04), T4 and T5 cattle had a greater percent of KPH fat compared with T1 cattle. Yasufuku-sired cattle (T5) had a greater 12th rib and 6th rib marbling score (P ≤ 0.01), USDA QG (P ≤ 0.01), 6th rib fat thickness (P ≤ 0.01) compared with T1 cattle. Fukutsuru-sired cattle (T4) had a lesser rib thickness

106 at the 6th rib location compared with T1 and T5 cattle. Yasufuku-sired cattle (T5) had a greater percentage of total lipid (P ≤ 0.01) and PUFA (P ≤ 0.01) compared with T1 and T4 cattle. Yasufuku-sired cattle (T5) also had a greater percentage of MUFA (P ≤ 0.02) and lesser percentage of SFA (P ≤ 0.01) compared with T1 cattle. Overall, Angus-sired steers had a greater ADG due to a greater DMI compared with Wagyu-sired cattle, while Yasufuku-sired cattle had a greater marbling deposition and desirable fatty acid composition in the Longissimus muscle compared with Angus-sired steers.

INTRODUCTION

The Angus breed is highly recognized for its production of highly marbled, high quality beef relative to other popular cattle breeds in the United States. However, the Wagyu breed, originally from Japan, has received increased interest in the U.S. due to their superior ability to deposit intramuscular fat, known as marbling. Beef production management is very different between the U.S. and Japan. In the U.S., cattle are placed into a feedlot and fed a high concentrate, corn-based diet as calves, shortly after weaning (~ 8 months of age), or as yearlings (~ 12 to 16 months of age). Cattle are typically sent to harvest when the group of cattle reaches a desired average body weight or fat thickness endpoint. In Japan, cattle are typically grown slower than in the U.S., where cattle are placed into a feedlot to consume a low vitamin A diet. At approximately 11 months of age, Wagyu cattle receive a low concentrate diet until they reach 18 months of age, and then cattle are transitioned to a high concentrate diet until they reach 28 to 30 months of age before harvest (Gotoh et al., 2014). In Japan, Wagyu cattle are raised to an age harvest endpoint to insure the Wagyu cattle have deposited sufficient intramuscular fat for the production of high quality beef. Although, questions remain whether Wagyu cattle can be as profitable in the feedlot as Angus cattle or if Wagyu cattle require extra time to deposit greater amounts of marbling compared with Angus cattle when raised in a U.S. based management production system. Therefore, it was hypothesized that Angus- sired cattle would have a greater rate of gain and a similar amount of marbling at a similar age and days on feed endpoint; however, Wagyu-sired cattle would have a greater marbling score compared with Angus-sired cattle with additional time to reach a similar 107 body weight endpoint. This study was designed to compare the feedlot performance, carcass characteristics, and fatty acid composition of Angus- and Wagyu-sired cattle when raised to a similar age or body weight endpoint in a U.S. based management production system. The effect of Wagyu sire will also be investigated to determine if Wagyu cattle selected for growth, as compared to marbling, perform differently in the feedlot and have different carcass characteristics.

MATERIALS AND METHODS

Experiment 1 was designed to compare Angus- and Wagyu-sired cattle at a similar age or days on feed (DOF). Angus-sired steers, representing treatment 1 (T1) were sired by GAR Sunrise (n = 7) and Carter Blackfoot 307 (n = 7). Treatment 2 (T2) consisted of Wagyu-sired steers (n = 5) and heifers (n = 4) sired by LMR Fukutsuru 729T, a bull selected for growth. Treatment 3 (T3) consisted of Wagyu-sired steers (n = 5) and heifers (n = 7) sired by OW Yasufuku 229Y, a bull selected for marbling ability. Angus-sired steers were removed from the feedlot for harvest when they reached the targeted body weight (BW) endpoint of 612 kg. Wagyu-sired steers and heifers from T2 and T3 were removed for harvest by blocking them with Angus-sired steers from T1. Experiment 2 treatments

Angus-sired steers (T1) from experiment 1 were used in the comparison with Wagyu-sired cattle at a similar BW endpoint (612 kg). Treatment 4 (T4) consists of Wagyu-sired steers (n = 4) and heifers (n = 5) sired by LMR Fukutsuru 729T. Treatment 5 (T5) consists of Wagyu-sired steers (n = 5) and heifers (n = 8) sired by OW Yasufuku

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229Y. Wagyu-sired steers and heifers from T4 and T5 were removed from the feedlot for harvest after reaching 612 kg and 566 kg, respectively. Feeding and management

Cattle used in the present study were born from SimAngus cows at the Jackson Agricultural Research Station (JARS; Jackson, OH) in March of 2017. Calves were weighed and weaned at seven months of age [205 ± 7.13 d of age (DOA)]. Calves were backgrounded for 54 d with free choice hay and a concentrate pellet, consisting of approximately 54% ground corn, 21%, corn gluten feed, 18% low-fat dried distillers grain, 3% soybean meal, 3% animal-vegetable fat blend, and the remainder consisting of Amaferm (BioZyme, St. Joseph, MO), vitamins, and minerals, before being transported to the Ohio Agricultural Research and Development Center (OARDC; Wooster, OH) feedlot. Upon arrival to the feedlot, calves were weighed, ear-tagged, administered Inforce 3 (Zoetis, Parsippany, NJ), and Vetmetric pour-on (MWI veterinary supply; Northern Ireland). Calves were placed into individual pens (2.6 × 1.5 m) consisting of concrete slatted floors, with a 1.5 m long concrete feed bunk, and ad libitum access to clean, fresh water. Diets were formulated to meet the nutrient requirements of growing and finishing beef cattle (NASEM, 2016), with the exception of excluding vitamin A from the supplement. Cattle were offered a growing diet for approximately 4 months (119 d) before making a switch to the finishing diet, which they consumed until removal for harvest (Table 14). Daily feed allocation and feed refusals were weighed prior to feeding to record individual feed intake. Feed samples were collected and saved every week to determine dry matter (DM) percentage (AOAC, 1984) and a composite sample of each dietary ingredient was analyzed for nutrient composition (Rock River Laboratory Inc., Wooster, OH). Weaning BW was collected at weaning, receiving BW was collected at the OARDC feedlot upon arrival, and off-test BW was collected at the OARDC feedlot before being transported to the Ohio State University abattoir (Columbus, OH).

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Carcass data collection

The following day after transport from the feedlot, final BW was collected prior to harvest, and afterwards, hot carcass weight (HCW) was collected. Carcasses were allowed to hang for 19.4 ± 3.45 d at 4 ºC. The right side of each carcass was split between the 6th and 7th ribs and between the 12th and 13th ribs to determine Japanese yield grade (YG; JMGA, 2008) and USDA YG (USDA, 2016), respectively. Between the 12th and 13th ribs, 12th rib backfat thickness (BFT), 12th rib longissimus muscle (LM) area, estimated percentage of kidney, pelvic, and heart fat (KPH), 12th rib USDA marbling score, USDA quality grade (QG), USDA YG, and percent boneless closely trimmed retail cuts (BCTRC) were determined. Between the 6th and 7th ribs, 6th rib BFT, 6th rib LM area, rib thickness (RT), 6th rib marbling score, and Japanese YG were determined. The adjustment factor of 2.049 was not applied to the Japanese YG of the Wagyu-sired carcasses in the present study (JMGA, 2008). Longissimus fatty acid composition

Fatty acid (FA) extraction and methylation processes used followed the procedures from Folch et al. (1957) and Doreau et al. (2007), respectively. A thin slice of the longissimus muscle at the 12th rib (~20 g) and 6th rib (~10 g) interfaces, free of subcutaneous fat and connective tissue, were collected and frozen for fatty acid composition analysis. Longissimus muscle samples were each ground in a blender to create a homogenous sample, from which 1 g of ground tissue was used in the same process as reported by Jaborek et al. (2019a, 2019b). Saturated fatty acid (SFA) percentage is the sum of 14:0, 16:0, and 18:0. Monounsaturated fatty acid (MUFA) percentage is the sum of 14:1, 16:1, and 18:1 isomers. Polyunsaturated fatty acid (PUFA) percentage is the sum of 18:2 isomers and 18:3. Additionally, ether extractable lipid and moisture percentage were determined from 1 g of ground LM tissue (AOAC, 1984). Statistical Analysis

Statistical analyses were performed using PROC MIXED in SAS (SAS Inst. Inc., Cary, NC). The experimental designs of both experiment 1 and 2 were randomized 110 incomplete block design with animal as the experimental unit. The statistical model used was: Yij = μ + Ti + sj + eij, where Ti = treatment as a fixed effect, and the random effect of sj = sex, and eij = random error. The statistical model used for FA composition was: Yijk th th = μ + Ti + Lj + TLij + sk + al + eijk, where Lj = LM location (6 or 12 rib), and TLij = treatment × location as fixed effects, and al = was a random effect. The REPEATED statement was used to determine the effect of FA composition by location, and the covariance structure with the lowest BIC was used. The LSMEANS and PDIFF statements were used to record treatment least square mean estimates, standard errors, and distinguish differences between the treatment levels. A significance of fixed effects and covariates was established at P ≤ 0.05 and tendencies are discussed at 0.05 < P ≤ 0.10.

RESULTS AND DISCUSSION

Experiment 1 (constant age and days on feed comparison)

For calves in experiment 1, birth weight was similar (P = 0.18). However, T1 calves tended to have a greater (P = 0.07) weaning weight compared with T2 calves and had a greater (P ≤ 0.05) weaning weight compared with T3 calves (Table 15). At feedlot entry, T1 calves continued to have a greater (P ≤ 0.03) weight compared with T3 calves, but a similar weight as T2 calves. The ADG of T1 cattle remained greater (P ≤ 0.04) than T3 cattle throughout the feeding period. Therefore, the off-test weight of T1 and T2 cattle were greater (P ≤ 0.01) than T3 cattle at a constant age. Over the course of the feeding period, T1 cattle had a greater (P ≤ 0.01) average daily DMI compared with cattle in T2 and T3. However, gain:feed (G:F; P = 0.22) and total DMI (P = 0.61) were similar between cattle being compared at a constant age endpoint. Since cattle in experiment 1 were compared at a similar DOF (248 ± 38.6 d) or DOA (503 ± 39.5 d), animal age at harvest (P = 0.52) and DOF (P = 0.26) were similar. Numerical differences for harvest age and DOF were due to T1 having a greater number of experimental units within their treatment as compared with T2 and T3.

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For cattle in experiment 1, T1 and T2 cattle had a greater (P ≤ 0.02) HCW compared with T3 cattle due to a greater (P ≤ 0.01) final BW (Table 16). At a different HCW and constant age, 12th rib BFT (P = 0.53), 12th rib LM area (P = 0.65), and USDA YG (P = 0.36) were similar between carcasses from cattle in different treatments. However, carcasses from T2 cattle had a greater (P ≤ 0.01) estimated KPH fat percentage compared with carcasses from T1 cattle, with carcasses from T3 cattle being intermediate. Most surprisingly, T3 carcasses had a greater (P ≤ 0.04) marbling score, which resulted in a greater (P ≤ 0.04) USDA QG, compared with T1 carcasses, with T2 cattle being intermediate. At the 6th rib, BFT (P = 0.11), LM area (P = 0.10), and RT (P = 0.28) were all similar, but the Japanese YG equation predicted a greater (P ≤ 0.04) retail yield from T1 carcasses compared with T2 and T3 carcasses. Similar to the 12th rib marbling score, the marbling score at the 6th rib tended (P = 0.06) to be greater from T3 carcasses compared with T1 carcasses. When compared at a constant DOA or DOF, T3 cattle already contained a greater percentage of total FA lipid (P ≤ 0.01) and ether extractable lipid (P ≤ 0.01) throughout the LM compared with T1 cattle (Table 17). The difference in total FA lipid and ether extractable lipid percentage are due to differences moisture content, as total FA lipid percentage is measured on a wet tissue basis and ether extractable lipid is measured on a dry tissue basis. There was an interaction between treatment and LM location for MUFA:SFA ratio (P ≤ 0.01) for the cattle in experiment 1. The magnitude of the difference for the MUFA:SFA ratio between the 12th rib compared with the 6th rib was greater for T3 cattle (1.08% vs. 1.02%) compared with T1 (1.02% vs. 1.00%) and T2 (1.00% vs. 0.97%) cattle. The MUFA:SFA ratio interaction was caused by the percentage of 18:1 cis 9 (P = 0.11) and the percentage of SFA (P = 0.11) also tending to have a similar treatment × LM location interaction as the MUFA:SFA ratio. The LM of T1 cattle had a greater percentage of 18:0 (P ≤ 0.04) and 18:3 (P ≤ 0.04) compared with the LM of T3 cattle, while the LM of T1 cattle also tended to have a greater percentage of 18:0 (P = 0.06), 18:1 trans isomers (P = 0.06), and 18:3 (P = 0.10) compared with the LM of T2 cattle. The LM of T3 cattle had a greater percentage of

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18:1 trans isomers (P ≤ 0.01) and 18:2 isomers (P ≤ 0.01) compared with the LM of T1 and T2 cattle. The percentage of SFA (P = 0.12) and MUFA (P = 0.20) in the LM did not differ between cattle from different treatments; however, the percent of PUFA in the LM was greater (P ≤ 0.01) for T3 cattle compared with the LM of T1 and T2 cattle. Therefore, the LM of T3 cattle had a greater (P ≤ 0.01) PUFA:SFA ratio when compared with the LM of T1 and T2 cattle. The LM had a greater (P ≤ 0.01) percentage of total lipid at the 6th rib compared with the 12th rib. In addition, the LM had a greater percentage of 18:0 (P ≤ 0.01), 18:1 trans isomers (P ≤ 0.01), and SFA (P ≤ 0.01) at the 6th rib compared with the 12th rib location. However, the 12th rib location had a greater percentage of 14:1 (P ≤ 0.01), 18:1 cis 9 (P ≤ 0.01), other 18:1 cis isomers (P ≤ 0.01), MUFA (P ≤ 0.01), and PUFA:SFA (P ≤ 0.01) compared with the 6th rib location of the LM. Lunt et al. (1993) compared Angus and Wagyu crossbred (75% to 87.5%) steers in the feedlot with a targeted rate of gain of 0.9 kg/d over the course of a 552 d feeding period; however, crossbred Wagyu steers were 253 d older and 40 kg heavier than Angus steers at the beginning of the feeding period. Therefore, as reported by Lunt et al. (1993), steers were not of similar age at the beginning of the feeding period, had a programmed feed intake, and were on feed for a much greater period of time, resulting in a much greater animal age at harvest (25.9 and 34.2 months, for Angus and Wagyu crossbred steers, respectively) as compared to cattle in the present experiment. Regardless of these differences, Angus steers had a greater ADG and reached a greater off-test BW with a greater feed efficiency compared with crossbred Wagyu steers during the feeding period (Lunt et al., 1993). Results of the present experiment are in partial agreement, as Fukutsuru-sired Wagyu cattle (T2) had a similar off-test BW, ADG, and G:F compared with Angus-sired cattle (T1), but Yasufuku-sired Wagyu cattle (T3) had a lesser off-test BW and ADG compared with Angus-sired steers when compared at a similar DOF and DOA. At the 12th and 6th rib locations, the carcass characteristics of steers reported by Lunt et al. (1993) were similar, with the exception of Japanese YG being greater for Wagyu crossbred steers when compared with Angus steers. In the present experiment,

113 the Japanese YG adjustment factor was not applied to Wagyu-sired carcasses; however, if it was applied, it is likely T2 and T3 cattle would have had a greater Japanese YG when compared with T1 cattle. In partial agreement to the results of the present experiment, Lunt et al. (1993) reported a greater percentage of ether extractable lipid in the LM (strip steaks) from crossbred Wagyu steers compared with Angus steers; however, the present study demonstrates this can vary by sire within breed. May et al. (1993) reported the subcutaneous (s.c.), dissected intramuscular (i.m.), and i.m.-free LM FA composition of the Angus and Wagyu steers reported by Lunt et al. (1993). In both the s.c. and i.m. fat, Wagyu steers had a greater percentage of 16:1, 18:1, and MUFA:SFA ratio, but a lesser percentage of 16:0 and 18:0 compared with Angus steers. The i.m.-free LM FA composition was similar to the s.c. and i.m. fat, but Wagyu steers had a greater percentage of 14:0 and 14:1, and a similar percentage of 18:1 compared with Angus steers (May et al., 1993). It is difficult to make direct comparisons with the LM FA composition reported by May et al. (1993), because the LM had i.m. fat dissected from it, unlike in the present experiment. Xie et al. (1996) compared the carcass characteristics and FA composition of Angus- and Wagyu-sired steers born from Angus × Hereford cows. In years 1 and 2, steers of unknown ages, with an initial BW of 391 kg and 433 kg, respectively, were fed. In year 1, steers consumed a 15% concentrate diet for 140 d, followed by a 85% concentrate diet for 170 d; while in year 2, steers consumed a 15% concentrate diet for 240 d. The HCW of Angus- and Wagyu-sired steers reported by Xie et al. (1996) were similar (~412 kg), but much larger than the cattle in the present experiment. Interestingly, that would imply that Angus- and Wagyu-sired steers had a similar ADG if they were the same age, which is in partial disagreement with the present experiment and what is commonly reported (Lunt et al., 1993; Lunt et al., 2005; Wertz et al. 2002). However, Xie et al. (1996) did not report feeding management details, such as the amount of feed offered and consumed by cattle in their study. In disagreement with the present experiment, Xie et al. (1996) reported a greater 12th rib LM area and lesser 12th rib BFT for Wagyu-sired steers when compared with Angus-sired steers; although, this

114 may be because of the large differences in HCW between these two studies. In agreement with the present experiment, Wagyu-sired steers had a greater percentage of KPH fat, USDA marbling score, and USDA QG when compared with Angus-sired steers. Wagyu sire had an effect on HCW, BFT, LMA, KPH, and USDA YG of Wagyu-sired carcasses (Xie et al., 1996). In the present experiment, we also observed Wagyu sire differences for HCW and percent KPH fat. Calles et al. (2000) reported that cattle sired by ‘new’ Wagyu sires (sires imported in 1993) had a greater LM area and marbling score compared with cattle sired by ‘old’ Wagyu sires (sires imported between 1974 and 1976). The LM FA composition of Wagyu-sired steers reported by Xie et al. (1996) had a greater percentage of 14:0, 14:1, 16:0, and 16:1 compared to Angus-sired steers, while Angus-sired steers had a greater percentage of 18:0, 18:2, PUFA, and PUFA:SFA ratio. However, Xie et al. (1996) reported 18:0, 18:2, and PUFA percentage were negatively correlated with marbling score. In the present experiment, 14:0, 16:0, 18:2, MUFA, PUFA, and PUFA:SFA ratio demonstrated a linear relationship (P ≤ 0.03) with total FA lipid percentage, with 18:1 cis 9 having a tendency (P = 0.07). Angus- and Wagyu-sired heifers were compared by Wertz et al. (2002) at two different age endpoints, as calves and 2-year olds. Heifer calves reported by Wertz et al. (2002) are most comparable to the cattle used in the present study, as heifers calves from Wertz et al. (2002) entered the feedlot at 9 months of age. However, these heifers calves were early weaned at 142 DOA and were offered a 80% concentrate diet for 119 d prior to feedlot entry. Another major difference between the present experiment and the study reported by Wertz et al. (2002) is the use of implants upon feedlot entry. Overall, heifer calves were in the feedlot for 238 d, similar to cattle in the present experiment, before being removed for harvest at approximately 16.4 months of age. Two-year old heifers were weaned at 180 d, grazed pasture for 16 months, entered the feedlot at approximately 22 months of age, and were offered feed until being removed for harvest 218 d later, at an age of approximately 29 months. Wagyu-sired heifer calves had a greater initial BW at feedlot entry compared to Angus-sired heifer calves, but BW differences were likely due to differences in age, as Wagyu-sired heifer calves were 17 d older (Wertz et al., 2002).

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Regardless, pre-weaning ADG would have been similar, which is in disagreement with the results of the present experiment that demonstrated that T1 cattle had a greater weaning BW compared with T3 cattle and tended to be greater than T2 cattle. The ADG of Angus-sired heifer calves was numerically greater (1.07 vs. 0.99 kg/d) compared to Wagyu-sired heifers, which resulted in heifer calves having a similar off-test BW (~481 kg). The ADG and off-test BW reported by Wertz et al. (2002) was less compared with the performance of cattle in the present experiment. It may be that heifers reported by Wertz et al. (2002) reached physiological maturity much sooner, as the result of consuming a high concentrate diet earlier in life. Angus-sired, 2-year heifers had a greater initial BW, ADG, DMI, and off-test BW, but tended to have a lesser G:F compared with Wagyu-sired, 2-year old heifers. Wagyu-sired heifer calves had a greater HCW compared with Angus-sired heifer calves, which may have been due to dressing percentage or the continuous trend of Wagyu-sired heifer calves being slightly heavier when compared with Angus-sired heifer calves. Wagyu-sired heifer calf carcasses also had a greater percentage of KPH fat, a greater 12th rib BFT and USDA YG, but a similar marbling score and percent ether extractable lipid from the LM when compared with carcasses from Angus-sired heifer calves. Interestingly, in the present study no differences in 12th rib BFT between Angus- and Wagyu-sired cattle were observed; however, Wagyu-sired cattle tended to have a greater BFT at the 6th rib in the present experiment. This difference may be due to the Angus and Wagyu sires used in the study, or the response each breed has to the administration of an anabolic implant. As 2-year old heifers, Angus-sired heifers had a greater 12th rib BFT compared with Wagyu-sired heifers. In another study, Lunt et al. (2005) compared Angus and Wagyu steers that were offered either a corn-based diet with a targeted 1.36 kg of gain/d to reach a BW of 525 and 650 kg after 8 and 16 months of feeding, or a hay-based diet supplemented with corn to achieve 0.9 kg of gain/d to reach a BW of 525 and 650 kg after 12 and 20 months of feeding, under U.S. or Japanese management strategies, respectively. The cattle in the present experiment are most comparable to the cattle offered the corn-based diet for 8

116 months in the U.S. production system reported by Lunt et al. (2005). Similar to the present experiment, Lunt et al. (2005) reported greater a greater initial BW for Angus steers compared with Wagyu steers at the start of the feeding period at 8 months of age. Additionally, Angus steers had a greater off-test BW and ADG when compared to Wagyu steers at a similar DOF, regardless of diet and management endpoint (Lunt et al., 2005). Angus-sired cattle from the present experiment had a similar ADG compared with Angus steers (~1.26 kg/d) reported by Lunt et al. (1993), but Wagyu-sired cattle from the present experiment had a greater ADG (1.15 kg/d) compared with Wagyu steers (1.03 kg/d) reported by Lunt et al. (2005). Differences between the ADG of Wagyu cattle from these two studies is likely due to genotype, as ADG tended to differ between Wagyu- sired cattle in T2 and T3 of the present experiment. Cattle from the present experiment had a greater off-test weight and HCW compared with the cattle reported by Lunt et al., (2005). As a result of greater ADG and HCW, carcasses in the present experiment had a substantially greater BFT (2.09 vs. 1.20 cm) and LM area (84.0 vs. 73.4 cm2) at the 12th rib location when compared with carcasses reported by Lunt et al. (2005). Additionally, Angus carcasses had a greater 12th rib BFT, tended to have a greater percent KPH fat, and had a less desirable USDA YG compared to Wagyu carcasses (Lunt et al., 2005). In the present experiment, BFT differences between the carcasses in different treatments were not observed. Lunt et al. (2005) reported that marbling score was not different between Angus and Wagyu steers; however, lipid percentage of the LM (thoracis) was greater from Angus carcasses when compared with Wagyu carcasses (9.3 vs. 6.1%). In partial agreement, the present experiment demonstrated that Wagyu-sired cattle can have a greater or similar marbling score and percentage of lipid in the LM compared to Angus- sired cattle depending on Wagyu sire or genotype. Chung et al. (2006) reported the FA composition of digesta, plasma, and s.c. fat from cattle reported by Lunt et al. (2005), but no measure of LM FA composition was made. Experiment 2 (constant body weight comparison)

Similar to experiment 1, the calves in experiment 2 had a similar birth weight (P = 0.68). At weaning the weight of calves was similar (P = 0.13); however, upon arriving to

117 the feedlot, T1 calves had a greater (P ≤ 0.02) weight when compared with T5 calves (Table 18). As a result of a lesser (P ≤ 0.01) ADG for T4 and T5 cattle compared with T1 cattle; T4 and T5 cattle required a greater (P ≤ 0.01) number of DOF compared with T1 cattle to reach a similar (P = 0.77) off-test BW. Interestingly, when compared at a similar BW endpoint, T4 and T5 cattle continued to have a lesser (P ≤ 0.01) DMI compared with T1 cattle. Such that T4 and T5 cattle, on average, consumed DM at approximately 1.9% of their BW and T1 cattle consumed DM at approximately 2.25% of their BW over the course of the feeding period. With additional DOF for T4 and T5 cattle, G:F (P ≤ 0.02) decreased, total DMI (P ≤ 0.01), and animal age at harvest (P ≤ 0.01) increased for T4 and T5 cattle compared with T1 cattle. Cattle compared at a similar BW endpoint in experiment 2 had a similar final BW (P = 0.88) and HCW (373 ± 19.1 kg; P = 0.51) as planned (Table 19). However, T5 cattle had a greater (P ≤ 0.04) dressing percentage compared to T1 and T4 cattle. Similar to experiment 1, there were no differences for 12th rib BFT (P = 0.48), 12th rib LM area (P = 0.64), and USDA YG (P = 0.16) between carcasses from cattle in different treatments, but T4 and T5 carcasses had a greater (P ≤ 0.01) estimated percentage of KPH fat compared with T1 carcasses. Carcasses from T5 cattle had a greater marbling score (P ≤ 0.01) and USDA QG (P ≤ 0.01) compared with carcasses from T1 and T4 cattle. At the 6th rib, T5 carcasses had a greater (P ≤ 0.01) BFT compared with T1 and T4 carcasses. Rib thickness measured at the 6th rib was greater (P ≤ 0.03) for T1 and T5 carcasses compared with T4 carcasses. There was no difference in LM area (P = 0.12) at the 6th rib between carcasses from cattle in different treatments. Altogether, the Japanese YG equation predicts a greater (P ≤ 0.01) retail yield from T1 cattle compared with T4 and T5 carcasses. Marbling score at the 6th rib was greater (P ≤ 0.01) from T5 carcasses compared with T1 carcasses. At a similar BW endpoint, the LM of T5 cattle had a greater (P ≤ 0.01) percentage of total FA lipid (P ≤ 0.01) and ether extractable lipid (P ≤ 0.01) compared with the LM of T1 and T4 cattle (Table 20). The percentage of 18:3 (P ≤ 0.04) and MUFA (P ≤ 0.04) had a treatment × LM location interaction for cattle in experiment 2. Interestingly, the

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LM had a numerically greater percentage of 18:3 at the 12th rib compared with the 6th rib location for T5 cattle (0.231% vs. 0.221%), but T1 and T4 cattle had a numerically lesser percentage of 18:3 in the 12th rib compared with the 6th rib location of the LM (0.221% vs. 0.228% and 0.206% vs. 0.220%, respectively). The magnitude of difference for MUFA percentage between the 12th and 6th rib was greater for T5 cattle (52.2% vs. 51.0%, respectively) compared with T1 cattle (48.0% vs. 47.5%, respectively), and T4 cattle demonstrated the opposite interaction with less MUFA in the 12th rib compared with the 6th rib of the LM (49.7% vs. 50.1%, respectively). The percentage of 16:0 (P = 0.06) and 18:1 cis 9 (P = 0.07) tended to have a treatment × LM location interaction, where T4 cattle had greater percentage of 16:0 and lesser percentage of 18:1 cis 9 in the LM at the 12th rib versus the 6th rib location when compared with T1 and T5 cattle. T1 cattle had a greater percentage of 18:0 in the LM compared to T4 and T5 cattle, which contributed to having a greater percentage of SFA in the LM compared with T5 (P ≤ 0.01) and T4 (P = 0.07) cattle. T5 cattle had a greater percentage of 18:1 cis 9 (P ≤ 0.01), other 18:1 cis isomers (P ≤ 0.01), and MUFA:SFA ratio (P ≤ 0.01) in the LM compared with T1 cattle, and T4 cattle tended to have a greater percentage of 18:1 cis 9 (P = 0.06), MUFA (P = 0.09), and MUFA:SFA ratio (P = 0.06) in the LM compared with T1 cattle. Yasufuku-sired cattle (T5) also had a greater percentage of 18:2 isomers (P ≤ 0.02), PUFA (P ≤ 0.01), and PUFA:SFA (P ≤ 0.01) in the LM compared with T1 and T4 cattle. The percentage of 18:2 isomers, MUFA, PUFA, and PUFA:SFA ratio displayed a linear relationship (P ≤ 0.03) with total FA lipid percentage. The 6th rib location of the LM had a greater percentage of total FA lipid (P ≤ 0.01) and ether extractable lipid (P ≤ 0.01) when compared with the 12th rib location of cattle compared at a similar BW endpoint. Cattle had a greater percentage of 18:0 (P ≤ 0.01), 18:1 trans isomers (P ≤ 0.01), and SFA (P ≤ 0.01) at the 6th rib compared with the 12th rib location of the LM. Whereas, the LM at the 12th rib had a greater percentage of 14:1 (P ≤ 0.01), 18:1 cis 9 (P ≤ 0.01), other 18:1 cis isomers (P ≤ 0.01), MUFA:SFA (P ≤ 0.01), and PUFA:SFA (P ≤ 0.01) when compared with the 6th rib location.

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Radunz et al. (2009) compared Angus- and Wagyu-sired cattle that were placed in the feedlot and adapted to a high concentrate diet after being early-weaned at 138 DOA. At a similar age, Wagyu-sired cattle tended to have a lesser weaning BW or initial BW compared with Angus-sired cattle at feedlot entry. In agreement with the present experiment, Radunz et al. (2009) reported Angus-sired cattle had a greater ADG and DMI that resulted in a lesser DOA (414 vs. 485 d) and DOF (272 vs. 349 d) compared with Wagyu-sired cattle. However, Radunz et al. (2009) reported a greater G:F for Wagyu-sired cattle when compared with Angus-sired cattle (0.180 vs. 0.175 kg/kg). The G:F of Angus-sired cattle in the present experiment was different depending on Wagyu sire, as T1 cattle were different from T5 cattle, but not T4 cattle. In agreement with the present experiment, Radunz et al. (2009) reported a similar 12th rib BFT and a greater percent KPH fat from Wagyu-sired carcasses when compared with Angus-sired carcasses; however, LM area tended to be greater from Wagyu-sired carcasses compared with Angus-sired carcasses. Slight differences in LM area may have been due to genotype or sire, as LM area differences between Angus and Wagyu cattle are not commonly reported. Wagyu-sired cattle had a greater USDA marbling score and ether extractable fat at the 12th rib compared with Angus-sired cattle (Radunz et al., 2009). As previously reported in experiment 1 and 2 of the present study, marbling or percent i.m. fat can vary depending on the Wagyu sires used in the study. At the 6th rib, Radunz et al. (2009) reported a greater LM area and BFT from Angus-sired carcasses compared with Wagyu-sired carcasses. In the present experiment, Angus-sired carcasses tended (P = 0.12) to have a greater 6th rib LM area when compared with Wagyu-sired carcasses because of the LM area difference between T1 and T4 carcasses. Interestingly, 6th rib BFT reported by Radunz et al. (2009) was much greater from Angus-sired carcasses when compared with Wagyu-sired carcasses (4.93 vs. 2.92 cm). This is in disagreement with the present experiment, as Angus-sired carcasses had a lesser BFT at the 6th rib compared with Wagyu-sired carcasses (2.80 vs. 3.42 cm). It may be possible that early- weaning or ionophore use resulted in a greater deposition of subcutaneous fat at the 6th rib location for Angus-sired cattle compared with the Wagyu-sired cattle reported in the

120 study by Radunz et al. (2009). Radunz et al. (2009) reported a greater Japanese YG for Wagyu-sired carcasses compared with Angus-sired carcasses, which is in disagreement with the present experiment, but is likely the cause of the differences in 6th rib BFT between the two experiments. Wagyu-sired cattle also had a greater percentage of ether extractable fat at the 6th rib location compared with Angus-sired cattle (Radunz et al., 2009). Summary

When compared after a similar DOF or at a similar BW, Wagyu cattle can perform differently in the feedlot and exhibit different carcass characteristics, as well as FA composition, when compared with Angus cattle. Wagyu calves are born at a light BW, although, sometimes comparable with Angus calves (Casas et al., 2012). Pre- weaning ADG tends to be lesser for Wagyu calves, which tends to result in a lesser weaning BW or feedlot entry BW compared with Angus calves. As cattle begin to consume a feedlot ration, Angus cattle have a greater ADG and final BW due to their greater DMI, but have a similar G:F when compared with Wagyu cattle. Interestingly, results from the present study demonstrate that Angus cattle consume feed at a greater percentage of their BW compared with Wagyu cattle. The present study and Calles et al. (2000) report that within the Wagyu breed, sire selection can affect the performance disparity between Wagyu- and Angus-sired cattle, as demonstrated in the present study, Fukutsuru-sired cattle performed more similarly to Angus-sired cattle in the feedlot than Yasufuku-sired cattle. However, if Wagyu cattle are going to be raised to a similar final BW as Angus cattle, Wagyu cattle are going to require additional DOF and will be older at harvest. Additional DOF after a long feeding period will decrease feedlot performance, with an increase in DMI, reduced ADG and G:F. Therefore, the feedlot performance disparity between Angus and Wagyu cattle will be even greater with additional DOF for Wagyu cattle compared with Angus cattle. With a similar DOF, Wagyu cattle have a lighter HCW, but relatively similar carcass characteristics when compared with Angus cattle. Although, the advanced rate of growth and physiological maturity of Angus cattle can result in a greater BFT compared to Wagyu cattle. Wagyu

121 cattle can have a greater percentage of KPH fat and greater or similar marbling score when compared with Angus cattle after a long period of feeding. Carcass characteristics at a similar BW, results in Wagyu cattle having a greater percentage of KPH fat and marbling score. Fatty acid composition differences are more difficult to discern between Angus and Wagyu cattle because management factors such as diet, DOF, and total lipid percentage can affect the outcome. As DOF and i.m. fat deposition increases in the LM, MUFA percentage increases and the relative percentage of SFA decreases primarily due to the deposition of 18:1 cis 9 (Duckett et al., 1993; Smith et al., 2009). Literature reports reviewed in this manuscript have reported greater percentages of 18:0, SFA, and occasionally PUFA for Angus cattle, while Wagyu cattle have a greater percentage of MUFA and occasionally PUFA in comparison. In the present study, differences in lipid deposition and FA composition of the LM muscle at the 6th and 12th rib locations were reported. Total lipid percentage was greater at the 6th rib compared to the 12th rib in both experiments in the present study. This pattern of LM lipid deposition at the 6th and 12th rib locations is in agreement with results reported by Radunz et al. (2009). Cook et al. (1964) and Zembayashi et al. (1995) have demonstrated that LM lipid content is deposited in greater quantities at the anterior and posterior extremities as compared with the medial part of the LM. It was interesting to observe differences in FA composition throughout different locations (6th vs. 12th thoracic rib) of the LM. Fatty acid composition differences due to location in experiment 1 were similar to experiment 2; therefore, the additional DOF for T4 and T5 in experiment 2 did not appear to affect the FA composition in the LM by location. Future research is needed to determine how FA composition may change by location throughout the LM of beef cattle. Implications In conclusion, sire selection within breed is very important and trait selection can ultimately affect the outcome of future progeny. For example, in the present study, selection of Angus sires for marbling ability can result in a similar i.m. fat deposition between Angus and Wagyu progeny; however, progeny from Wagyu sires selected for

122 marbling appear to deposit a greater amount i.m. fat than Angus progeny selected for marbling ability at a similar age and body weight. Interestingly, Angus-sired cattle had a much greater DMI on a body weight basis when compared with Wagyu-sired cattle, although, there were no differences in feed efficiency. In addition to a greater percentage of i.m fat, Yasufuku-sired cattle, had a more desirable LM FA composition. Therefore, it appears Wagyu cattle can be selected to have a superior amount of i.m. fat, with a desirable FA composition compared with Angus cattle at a similar age (16.5 months). Future research may be needed to see if i.m. fat differences still exist at a younger age and with fewer DOF.

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LITERATURE CITED

AOAC. 1984. Official Methods of Analysis, 14th Ed. Association of Official Analytical Chemists, Washington, DC, USA. Casas, E., R. M. Thallman, and L. V. Cundiff. 2012. Birth and weaning traits in crossbred cattle from Hereford, Angus, Norwegian Red, Swedish Red and White, Wagyu, and Friesian sires. J. Anim. Sci., 90: 2916-2920. doi:10.2527/jas.2011- 4694 Chung, K. Y., D. K. Lunt, C. B. Choi, S. H. Chae, R. D. Rhoades, T. H. Adams, B. Booren, and S. B. Smith. 2006. Lipid characteristics of subcutaneous adipose tissue and M. longissimus thoracis of Angus and Wagyu steers fed to US and Japanese endpoints. Meat Sci., 73: 432-441. doi.org/10.1016/j.meatsci.2006.01.002 Cook, C. F., R. W. Bray, and K. G. Weckel. 1964. Variations in the quantity and distribution of lipid in the bovine Longissimus dorsi. J. Anim. Sci., 23: 329-331. doi.org/10.2527/jas1964.232329x Doreau, M., D. Rearte, J. Portelli, and J. L. Peyraud. 2007. Fatty acid ruminal metabolism and digestibility in cows fed perennial ryegrass. Euro. J. Lipid Sci. Tech., 109: 790-798. doi:10.1002/ejlt.200700003 S. K. Duckett, D. G. Wagner, L. D. Yates, H. G. Dolezal, and S. G. May. 1993. Effects of time on feed on beef nutrient composition. J. Anim. Sci., 71: 2079–2088. doi.org/10.2527/1993.7182079x Elias Calles, J. A., C. T. Gaskins, J. R. Busboom, S. K. Duckett, J. D. Cronrath, J. J. Reeves,and R. W. Wright Jr. 2000. Differences among Wagyu sires for USDA carcass traits and palatability attributes of cooked ribeye steaks. J. Anim. Sci., 78: 1710-1715. doi.org/10.2527/2000.7871710x FASS, 2010. Guide for the care and use of agricultural animals in agricultural research and teaching. Consortium for developing a guide for the care and use of agricultural animals in agricultural research and teaching. Fed. Anim. Sci. Soc. (Champaign, IL).

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Folch, J., M. Lees, and G. H. Sloane Stanley. 1957. A simple method for the isolation and purification of total lipids from animal tissues. J. Biol. Chem., 226: 497-509. Gotoh, T., H. Takahashi, T. Nishimura, K. Kuchida, and H. Mannen. 2014. Meat produced by Japanese Black cattle and Wagyu. Anim. Front., 4: 46-54. doi.org/10.2527/af.2014-0033 Jaborek, J. R., H. N. Zerby, S. J. Moeller, A. E. Relling, and F. L. Fluharty. 2019a. Evaluation of feedlot performance, carcass characteristics, carcass retail cut distribution, Warner-Bratzler shear force, and fatty acid composition of purebred Jersey and crossbred Jersey steers. Trans. Anim. Sci. Jaborek, J. R., H. N. Zerby, S. J. Moeller, A. E. Relling, and F. L. Fluharty. 2019b. Evaluation of feedlot performance, carcass characteristics, carcass retail cut distribution, Warner-Bratzler shear force, and fatty acid composition of crossbred Jersey steers and heifers. Appl. Anim. Sci. JMGA. 2008. Beef carcass grading standards. Japan Meat Grading Association. Tokyo, Japan. Lunt, D. K., R. R. Riley, and S. B. Smith. 1993. Growth and carcass characteristics of Angus and American Wagyu steers. Meat Sci., 34: 327-334. doi.org/10.1016/0309-1740(93)90081-R Lunt, D. K., K. Y. Chung, C. B. Choi, and S. B. Smith. 2005. Production characteristics and carcass quality of Angus and Wagyu steers fed to US and Japanese endpoints. J. Anim. Vet. Adv., 4: 949-953. doi=javaa.2005.949.953 May, S. G., C. A. Sturdivant, D. K. Lunt, R. K. Miller, and S. B. Smith. 1993. Comparison of sensory characteristics and fatty acid composition between Wagyu crossbred and Angus steers. Meat Sci., 35: 289-298. doi.org/10.1016/0309- 1740(93)90034-F National Academies of Sciences, Engineering, and Medicine. 2016. Nutrient Requirements of Beef Cattle: Eighth Revised Edition. Washington, DC: The National Academies Press.

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Radunz, A. E., S. C. Loerch, G. D. Lowe, F. L. Fluharty, and H. N. Zerby. 2009. Effect of Wagyu- versus Angus-sired Calves on Feedlot Performance, Carcass Characteristics, and Tenderness. J. Anim. Sci. 87: 2971-976. doi:10.2527/jas.2009-1914 Smith, S. B., C. A. Gill, D. K. Lunt, and M. A. Brooks. 2009. Regulation of fat and fatty acid composition in beef cattle. Asian-Aust. J. Anim. Sci., 22: 1225-1233. doi.org/10.5713/ajas.2009.r.10 USDA. 2016. United States Standards for Grades of Carcass Beef. USDA, Washington, DC. Wertz, A. E., L. L. Berger, P. M. Walker, D. B. Faulkner, F. K. McKeith, and S. L. Rodriguez-Zas,. 2002. Early-weaning and postweaning nutritional management affect feedlot performance, carcass merit, and the relationship of 12th-rib fat, marbling score, and feed efficiency among Angus and Wagyu heifers. J. Anim. Sci., 80: 28-37. doi.org/10.2527/2002.80128x Xie, Y. R., J. R. Busboom, C. T. Gaskins, K. A. Johnson, J. J. Reeves, R. W. Wright, J. D. Cronrath. 1996. Effects of breed and sire on carcass characteristics and fatty acid profiles of crossbred Wagyu and Angus steers. Meat Sci., 43: 167-177. doi:10.1016/0309-1740(96)84588-8 Zembayashi, M., K. Nishimura, D. K. Lunt, and S. B. Smith. 1995. Effect of breed type and sex on the fatty acid composition of subcutaneous and intramuscular lipids of finishing steers and heifers. J. Anim. Sci., 73: 3325-3332. doi.org/10.2527/1995.73113325x

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Table 14. Composition (%) of diets offered during the experiment on a dry matter basis Growing Finishing Ingredient Whole shelled corn 17.50 55.00 DDGS 17.50 10.00 Corn silage 55.00 25.00 Supplement 10.00 10.00 Ground corn 1.12 1.51 Soybean meal 5.00 5.00 Digest More 1 0.78 0.39 Limestone 1.10 1.10 White salt 1.00 1.00 Urea 0.50 0.50 Vit. A, 30,000 IU/g 0.00 0.00 Vit. D, 3,000 IU/g 0.01 0.01 Vit. E, 44 IU/g 0.02 0.02 Selenium, 201 ppm 0.14 0.14 Potassium Chloride 0.30 0.30 Copper Sulfate 0.01 0.01 Zinc Sulfate 0.02 0.02 Magnesium Sulfate 0.01 0.01

Analyzed composition Crude protein, % 14.22 12.90 NDF, % 28.18 17.09 Fat, % 3.71 3.59 Ca, % 0.52 0.45 P, % 0.35 0.33 NEm, Mcal/kg 2.01 2.21 NEg, Mcal/kg 1.35 1.52 1 Amaferm (BioZyme, St. Joesph, MO)

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Table 15. Feedlot performance of Angus- and Wagyu-sired cattle raised to a similar age and days on feed endpoint Treatment 1 Item T1 T2 T3 SEM 2 P-value Weaning weight, kg 244 a 235 ab 220 b 11.6 0.04 Receiving weight, kg 276 a 257 ab 247 b 13.7 0.02 Off-test weight, kg 585 a 571 a 528 b 42.5 0.01

ADG, kg/d 1.26 a 1.20 ab 1.10 b 0.114 0.04 DMI, kg/d 8.91 a 8.11 b 7.87 b 0.627 0.01 G:F, kg/kg 0.143 0.147 0.139 0.0042 0.22

Total DMI, kg 2052 2133 1983 207 0.61 DOF, d 235 263 250 12.7 0.26 Harvest age, d 495 515 503 13.3 0.52 a, b Treatment lsmean estimates within a row, with a different superscript differ (P ≤ 0.05). 1 T1 = Angus-sired steers, T2 = Fukutsuru-sired Wagyu cattle, T3 = Yasufuku-sired Wagyu cattle. 2 The reported standard error of the mean is the greatest between the different treatments.

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Table 16. Carcass characteristics of Angus- and Wagyu-sired cattle with a similar age and days on feed endpoint Treatment 1 Item T1 T2 T3 SEM 2 P-value Final weight, kg 550 a 554 a 506 b 45.1 0.01 HCW, kg 350 a 357 a 326 b 32.2 0.02 Dressing percent, % 63.79 64.36 64.31 0.694 0.62 12th Rib LM area, cm2 85.3 84.8 81.9 5.67 0.65 Fat thickness, cm 2.07 2.29 1.93 0.240 0.53 KPH, % 2.47 3.33 2.87 0.152 0.01 USDA YG 3 3.77 c 4.20 a 3.64 b 0.303 0.36 BCTRC, % 4 47.98 47.00 48.35 0.705 0.35 USDA QG 5 11.80 b 12.23 ab 12.83 a 0.323 0.04 Marbling score 6 631 b 655 ab 728 a 32.0 0.04 6th Rib LM area, cm2 45.3 43.3 41.1 3.30 0.10 Fat thickness, cm 2.78 3.23 3.11 0.168 0.11 Rib thickness, cm 7.32 6.80 6.72 0.364 0.28 Japanese YG, % 7 71.24 a 70.18 b 70.34 b 0.279 0.01 Marbling score 6 648 694 743 33.6 0.06 a, b Treatment lsmean estimates within a row, with a different superscript differ (P ≤ 0.05). 1 T1 = Angus-sired steers, T2 = Fukutsuru-sired Wagyu cattle, T3 = Yasufuku-sired Wagyu cattle. 2 The reported standard error of the mean is the greatest between the different treatments. 3 Yield grade = 2.5 + (2.5 × (12th rib fat thickness / 2.54)) + (0.2 × % KPH fat) + (0.0038 × HCW / 0.453592)) - (0.32 × (LM area / 6.4516)). 4 BCTRC (Boneless closely trimmed retail cuts) = 51.34 - (2.28 × (12th rib fat thickness)) - (0.462 × % KPH fat) - (0.02 × (HCW)) + (0.1147 × (LM area)). 5 USDA quality grade is based on a numeric scale: 11 = average choice, 12 = high choice. 6 Marbling score is based on a numeric scale: 600-699 = moderate, 700-799 = slightly abundant. 7 Japanese YG = 67.37 + (0.13 × (LM area / 6.4516)) + (0.667 × (6th rib fat thickness / 2.54)) - (0.025 × (carcass side weight / 0.453592)) - (0.896 × (6th rib thickness / 2.54)).

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Table 17. Longissimus muscle fatty acid composition (%) of Angus- and Wagyu-sired cattle with a similar age and days on feed endpoint Treatment 1 Location P-value Item T1 T2 T3 SEM 2 6th rib 12th rib SEM 2 TRT LOC T×L Ether extractable lipid 10.06 b 10.99 b 14.13 a 1.057 12.46 y 10.99 z 0.610 0.01 0.01 0.32 Total fatty acid lipid 7.82 b 8.95 b 11.39 a 0.890 10.40 y 8.37 z 0.494 0.01 0.01 0.64

14:0 2.95 3.17 3.10 0.106 3.08 3.07 0.058 0.28 0.78 0.34 14:1 0.62 0.83 0.68 0.077 0.67 z 0.75 y 0.041 0.13 0.01 0.68 16:0 27.62 28.19 27.61 0.320 27.90 27.72 0.176 0.32 0.12 0.32 16:1 3.41 3.75 3.57 0.173 3.52 3.63 0.109 0.35 0.37 0.71 18:0 14.75 a 13.32 ab 13.04 b 0.565 14.15 y 13.26 z 0.300 0.04 0.01 0.43 18:1 trans 1.29 b 1.12 b 1.47 a 0.069 1.38 y 1.22 z 0.037 0.01 0.01 0.61 18:1 cis 9 40.25 40.79 41.09 0.522 40.48 z 40.94 y 0.279 0.41 0.01 0.11 18:1 cis others 2.18 2.27 2.35 0.080 2.21 z 2.32 y 0.042 0.22 0.01 0.22

1 b b a 30 18:2 2.43 2.30 2.81 0.098 2.50 2.53 0.054 0.01 0.34 0.31

18:3 0.22 a 0.20 ab 0.18 b 0.013 0.20 0.20 0.007 0.04 0.23 0.34

SFA 45.32 44.68 43.75 0.613 45.12 y 44.05 z 0.328 0.12 0.01 0.11 MUFA 47.76 48.75 49.16 0.652 48.26 z 48.85 y 0.356 0.20 0.01 0.66 PUFA 2.65 b 2.50 b 2.99 a 0.098 2.70 2.73 0.056 0.01 0.40 0.29 MUFA:SFA 0.99 1.01 1.05 0.027 1.00 z 1.04 y 0.014 0.13 0.01 0.01 PUFA:SFA 0.059 b 0.056 b 0.069 a 0.003 0.060 z 0.062 y 0.002 0.01 0.01 0.21 a, b Treatment lsmean estimates within a row, with a different superscript differ (P ≤ 0.05). y, z Location lsmean estimates within a row, with a different superscript differ (P ≤ 0.05). 1 T1 = Angus-sired steers, T2 = Fukutsuru-sired Wagyu cattle, T3 = Yasufuku-sired Wagyu cattle. 2 The reported standard error of the mean is the greatest between the different treatments.

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Table 18. Feedlot performance of Angus- and Wagyu-sired cattle raised to a similar body weight endpoint Treatment 1 Item T1 T4 T5 SEM 2 P-value Weaning weight, kg 245 236 222 12.3 0.13 Receiving weight, kg 278 a 264 ab 244 b 13.4 0.02 Off-test weight, kg 595 592 590 20.5 0.77

ADG, kg/d 1.36 a 1.13 b 1.06 b 0.043 0.01 DMI, kg/d 9.40 a 8.17 b 8.04 b 0.279 0.01 G:F, kg/kg 0.145 a 0.139 ab 0.132 b 0.0034 0.02

Total DMI, kg 2164 b 2360 a 2627 a 111 0.01 DOF, d 235 b 294 a 328 a 15.4 0.01 Harvest age, d 495 b 547 a 579 a 15.9 0.01 a, b Treatment lsmean estimates within a row, with a different superscript differ (P ≤ 0.05). 1 T1 = Angus-sired steers, T4 = Fukutsuru-sired Wagyu cattle, T5 = Yasufuku-sired Wagyu cattle. 2 The reported standard error of the mean is the greatest between the different treatments.

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Table 19. Carcass characteristics of Angus- and Wagyu-sired cattle raised to a similar body weight endpoint Treatment 1 Item T1 T4 T5 SEM 2 P-value Final weight, kg 570 573 570 23.6 0.88 HCW, kg 366 367 373 15.8 0.51 Dressing percent, % 64.24 b 64.10 b 65.39 a 0.428 0.04 12th Rib LM area, cm2 86.7 84.4 87.6 4.52 0.64 Fat thickness, cm 2.10 2.44 2.38 0.242 0.48 KPH, % 2.45 b 3.61 a 3.46 a 0.178 0.01 USDA YG 3 3.79 4.52 4.32 0.307 0.16 BCTRC, % 4 47.98 46.26 46.71 0.700 0.14 USDA QG 5 11.90 12.32 13.51 0.379 0.01 Marbling score 6 638 b 684 b 785 a 36.1 0.01 6th Rib LM area, cm2 47.4 43.5 45.6 1.64 0.12 Fat thickness, cm 2.80 b 3.20 b 3.64 a 0.164 0.01 Rib thickness, cm 7.47 a 6.66 b 7.41 a 0.241 0.03 Japanese YG, % 7 71.36 a 70.02 b 70.33 b 0.234 0.01 Marbling score 6 653 b 721 ab 778 a 37.6 0.01 a, b Treatment lsmean estimates within a row, with a different superscript differ (P ≤ 0.05). 1 T1 = Angus-sired steers, T4 = Fukutsuru-sired Wagyu cattle, T5 = Yasufuku-sired Wagyu cattle. 2 The reported standard error of the mean is the greatest between the different treatments. 3 Yield grade = 2.5 + (2.5 × (12th rib fat thickness / 2.54)) + (0.2 × % KPH fat) + (0.0038 × HCW / 0.453592)) - (0.32 × (LM area / 6.4516)). 4 BCTRC (Boneless closely trimmed retail cuts) = 51.34 - (2.28 × (12th rib fat thickness)) - (0.462 × % KPH fat) - (0.02 × (HCW)) + (0.1147 × (LM area)). 5 USDA quality grade is based on a numeric scale: 11 = average choice, 12 = high choice. 6 Marbling score is based on a numeric scale: 600-699 = moderate, 700-799 = slightly abundant. 7 Japanese YG = 67.37 + (0.13 × (LM area / 6.4516)) + (0.667 × (6th rib fat thickness / 2.54)) - (0.025 × (carcass side weight / 0.453592)) - (0.896 × (6th rib thickness / 2.54)).

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Table 20. Longissimus muscle fatty acid composition (%) of Angus- and Wagyu-sired cattle raised to a similar body weight endpoint Treatment 1 Location P-value Item T1 T4 T5 SEM 2 6th rib 12th rib SEM 2 TRT LOC T×L Ether extractable lipid 10.06 b 11.43 b 15.98 a 1.070 13.75 y 11.24 z 0.619 0.01 0.01 0.65 Total fatty acid lipid 7.82 b 9.34 b 12.85 a 0.982 10.72 y 9.28 z 0.542 0.01 0.01 0.77

14:0 2.95 2.77 2.82 0.110 2.85 2.85 0.059 0.39 0.83 0.31 14:1 0.62 0.69 0.73 0.059 0.64 z 0.72 y 0.032 0.35 0.01 0.71 16:0 27.62 27.33 26.72 0.451 27.27 27.17 0.239 0.24 0.41 0.06 16:1 3.41 3.37 3.80 0.213 3.48 3.58 0.134 0.21 0.53 0.24 18:0 14.75 a 13.09 b 12.00 b 0.570 13.68 y 12.88 z 0.327 0.01 0.01 0.43 18:1 trans 1.29 1.21 1.40 0.077 1.37 y 1.23 z 0.042 0.19 0.01 0.87 18:1 cis 9 40.25 b 42.22 ab 43.07 a 0.746 41.69 z 42.00 y 0.389 0.01 0.01 0.06 18:1 cis others 2.18 b 2.36 ab 2.60 a 0.109 2.35 z 2.42 y 0.057 0.01 0.01 0.12 133 18:2 2.43 b 2.52 b 2.84 a 0.118 2.57 2.62 0.063 0.02 0.15 0.29

18:3 0.22 0.21 0.23 0.017 0.22 0.23 0.009 0.83 0.30 0.04

SFA 45.32 a 43.19 ab 41.64 b 0.842 43.80 y 42.91 z 0.439 0.01 0.01 0.21 MUFA 47.76 b 49.86 ab 51.59 a 0.896 49.53 49.94 0.476 0.01 0.09 0.04 PUFA 2.65 b 2.73 b 3.06 a 0.120 2.79 2.84 0.064 0.02 0.17 0.38 MUFA:SFA 0.99 b 1.09 ab 1.17 a 0.040 1.07 z 1.10 y 0.021 0.01 0.01 0.23 PUFA:SFA 0.059 b 0.063 b 0.074 a 0.003 0.064 z 0.067 y 0.002 0.01 0.01 0.64 a, b Treatment lsmean estimates within a row, with a different superscript differ (P ≤ 0.05). y, z Location lsmean estimates within a row, with a different superscript differ (P ≤ 0.05). 1 T1 = Angus-sired steers, T4 = Fukutsuru-sired Wagyu cattle, T5 = Yasufuku-sired Wagyu cattle. 2 The reported standard error of the mean is the greatest between the different treatments.

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Chapter 7. Lipid metabolism gene expression of the Longissimus muscle from Angus- and Wagyu-sired cattle when raised to a similar age or body weight

ABSTRACT

The present study investigates post-weaning Longissimus muscle (LM) gene expression associated with intramuscular fat development and growth in Angus- and Wagyu-sired steers raised to a similar age and similar days on feed (DOF) or body weight (BW). Angus-sired steers (T1) were compared with steers from two different Wagyu bulls, Fukutsuru and Yasufuku, selected for growth or marbling, to be compared at a similar DOF (T2 and T3) or BW (T4 and T5), respectively. It was hypothesized Wagyu-sired steers would exhibit more adipogenic waves compared with Angus-sired steers, which would explain differences in marbling accumulation. Prostacyclin synthase expression may indicate the initiation of two adipogenic waves occurring around 7 and 17 months of age in the steers in the present study. These two peaks were also associated with the upregulation of oxidative genes. After 11 months of age, the expression of early and late differentiation markers began to increase and was followed by an upregulation of genes responsible for fatty acid and triglyceride synthesis at 14 months of age. Yasufuku-sired steers had a greater (P ≤ 0.01) percentage of ether extractable lipid in the LM compared with Fukutsuru- and Angus-sired steers. Greater expression of peroxisome proliferator activated receptor (PPAR) delta by Yasufuku-sired steers at 9 and 11 months of age may indicate an extended or additional proliferative period for pre-adipocytes within the LM. Interestingly, Yasufuku-sired steers had a greater expression of oxidative genes, hormone sensitive lipase and monoglyceride lipase, which may be associated with the energy expenditure needed for the initiation of differentiation by pre-adipocytes. Yasufuku-sired steers also had a greater expression of PPAR gamma and expression was upregulated earlier in life compared with Fukutsuru- and Angus-sired steers. Greater expression of PPAR gamma by Yasufuku-sired steers may explain the tendency for greater expression of fatty acid elongase 6 and stearoyl-CoA desaturase. These results may help explain the differences in marbling accumulation between the different treatments of steers used in this study.

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INTRODUCTION

Marbling, also known as intramuscular fat (IMF), can be visually recognized as the deposition of fat between the muscle fibers within the muscle bundles of the muscle (Moody and Cassens, 1968). Marbling has been reported to have a positive impact on the three sensory characteristics, tenderness, juiciness, and flavor, that affect beef eating quality and increase consumer acceptability (May et al., 1992; Platter et al., 2003; Killinger et al., 2004). As an indication of eating quality and value, marbling score is extremely influential in determining beef carcass USDA quality grade. Therefore, considerable interest has been directed towards expanding the knowledge focused on IMF development and growth. Intramuscular adipocytes develop from mesenchymal progenitor cells in a process known as adipogenesis. Adipogenesis begins with the commitment or determination of mesenchymal stem cells to the adipose tissue lineage and formation of fibro/adipogenic progenitor cells, also known as pre-adipocytes. A cell signaling cascade allows pre-adipocytes to proliferate, followed by the switch to differentiation of pre-adipocytes into mature adipocytes through the incorporation and storage of triglycerides. Different breeds of cattle or cattle with different genotypes can result in significant differences in marbling deposition. For example, Wagyu cattle are known for their ability to deposit extreme amounts of IMF compared to cattle breeds commonly used in the United States, such as Angus (Lunt et al., 1993; Lunt et al., 2005). Previous research indicates the critical time where pre-adipocytes undergo proliferation in cattle is approximately 7 months of age, with early differentiation occurring around 12 months of age, followed by increased IMF hypertrophy (Wang et al., 2009). The objective of the present study was to increase the understanding of the cellular signaling pathways responsible for marbling differences in cattle with different genotypes over time at a similar age endpoint, with a similar number of days consuming a feedlot ration, or at a similar body weight endpoint. Genes analyzed in the present study are representative of adipogenesis, angiogenesis, fatty acid synthesis and transport, triglyceride synthesis, and lipolysis signaling pathways. We hypothesized that the expression of genes responsible for marbling accumulation would display different patterns between Angus- and Wagyu-sired steers. For example, additional gene expression peaks demonstrating proliferation or differentiation of

135 pre-adipocytes may be present for Wagyu-sired steers compared with Angus-sired steers, which could explain differences in marbling scores.

MATERIALS AND METHODS

Experiment 1 was designed to compare Angus- and Wagyu-sired steers at a similar age or days on feed (DOF). Angus-sired steers, representing treatment 1 (T1) were sired by GAR Sunrise (n = 6). Treatment 2 (T2) consists of Wagyu-sired steers (n = 5) sired by LMR Fukutsuru 729T. Treatment 3 (T3) consists of Wagyu-sired steers (n = 5) sired by OW Yasufuku 229Y. LMR Fukutsuru 729T was selected for a greater rate of gain, while OW Yasufuku 229Y was selected for a greater ability to accumulate marbling. Angus-sired steers were removed from the feedlot for harvest when they reached the targeted body weight (BW) endpoint of 612 kg. Wagyu-sired steers from T2 and T3 were removed for harvest by blocking them with Angus-sired steers from T1. Experiment 2 treatments

Angus-sired steers (T1) from experiment 1 were used in the comparison with Wagyu- sired cattle at a similar BW endpoint (612 kg). Treatment 4 (T4) consists of Wagyu-sired steers (n = 4) sired by LMR Fukutsuru 729T. Treatment 5 (T5) consists of Wagyu-sired steers (n = 5) sired by OW Yasufuku 229Y. Wagyu-sired steers from T4 and T5 were removed from the feedlot for harvest after reaching 612 kg. Management, feeding, and biopsy collection

136 vegetable fat blend, and the remainder consisting of Amaferm (BioZyme, St. Joseph, MO), vitamins, and minerals) before being transported to the Ohio Agricultural Research and Development Center (OARDC; Wooster, OH) feedlot. Upon receiving to the feedlot, calves were weighed, ear-tagged, and administered Inforce 3 (Zoetis, Parsippany, NJ) and Vetmetric pour-on (MWI veterinary supply; Northern Ireland). Calves were placed into individual pens (2.6 × 1.5 m) consisting of concrete slatted floors, with a 1.5 m long concrete feed bunk, and ad libitum access to clean, fresh water. Diets were formulated to meet the nutrient requirements of growing and finishing beef cattle (NASEM, 2016), with the exception of excluding vitamin A from the supplement. Steers were offered a growing diet for approximately 4 months (119 d) before making a 21 d switch to the finishing diet, which they consumed until removal for harvest (Table 21). Weaning BW was collected at weaning, receiving BW was collected at the OARDC feedlot upon arrival, and off- test BW was collected at the OARDC feedlot before being transported to the Ohio State University abattoir (Columbus, OH). Carcass data collection and fatty acid composition procedures and results were reported previously in chapter 6. Biopsies were collected at the average age of 205, 268, 331, 422, and 513 d for experiment 1 steers. Steers in experiment 2 weighed 241 ± 18.4, 296 ± 24.3, 400 ± 33.9, 531 ± 33.3, and 613 ± 18.0 kg and were 205 ± 9.5, 280 ± 10.0, 352 ± 16.3, 458 ± 31.9, and 546 ± 50.1 DOA at the 5 biopsy collections. The longissimus muscle (LM) was biopsied on the left side beginning at the 12th rib. Subsequent biopsies were collected approximately 2.54 cm posterior from the previous biopsy site, evident by scarring. Prior to surgery, the biopsy site was clipped to remove the hair and scrubbed 3 times with betadine surgical scrub, followed by alcohol. Administration of 5 ml of lidocaine was administered prior to making a 2.54 cm incision to place the biopsy needle. A 10 mm muscle biopsy cannula (Millennium Surgical Corporation; Narberth, PA) was used to collect approximately 1 g of LM tissue. The biopsy incision site was stapled and sprayed with a water resistant aerosol bandage (Aluspray; Neogen Corporation; Lexington, KY). Biopsies were snap frozen with liquid nitrogen and stored in the freezer at -80 °C. The harvest LM biopsy was collected from the LM of the carcass immediately after hide removal with a knife and frozen.

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RNA extraction and analysis

Extraction of RNA was performed using RNAzol® RT (Molecular Research Center; Cincinnati, OH) according to the manufacturer’s instructions. Briefly, 1 ml of RNAzol® RT and 0.15 g of 0.1 mm zirconium beads were placed into a 2 ml micro-centrifuge tube, along with 0.1 g of biopsied LM tissue, and chilled on ice. Samples were homogenized for 1 min with a bead beater, chilled on ice for 1 min, and repeated. RNase-free water (0.4 ml) was added, the sample was vortexed for 15 s, and allowed to incubate for 15 min at room temperature. Next, samples were centrifuged at 12,000 × g for 5 min at 4 °C. After, 0.6 ml of supernatant was pipetted into 2 new micro-centrifuge tubes each, containing 0.4 ml of isopropanol, vortexed for 2 s, and allowed to incubate for 10 min at room temperature, before centrifuging at 12,000 × g for 10 min at 4 °C. Supernatant was discarded, 0.4 ml of 75% ethanol was pipetted into each tube, and centrifuged 4,000 × g for 3 min at 20 °C. After repeating the last step, the RNA pellet was allowed to dry and 10 µl of RNase-free water was pipetted into each tube to re-suspend the RNA pellet. The two centrifuge tubes containing RNA were combined and frozen at -80 °C until further analysis. Extracted RNA was quantified using UV spectroscopy (NanoDrop Technologies; Wilmington, DE) and RNA integrity was assessed using a BioAnalyzer 2100 and RNA NanoChip assay (Agilent Technologies; Santa Clara, CA). Gene expression was determined using a NanoString nCounter XT Assay (NanoString Technologies; Seattle, WA). The nSolver Analysis Software 3.0 (NanoString Technologies, Seattle, WA) was used to analyze nCounter data. Data were normalized to the geometric mean of the reference genes: actin-beta, cyclophilin A, and hypoxanthine phosphoribosyltransferase 1 (Table 22). Statistical Analysis

Statistical analyses were performed using PROC MIXED in SAS (SAS Inst. Inc., Cary, NC). The experimental designs of both experiment 1 and 2 were randomized complete block design with animal as the experimental unit. The statistical model used was: Yij = μ + Ti + Bj +

TBij + ak + eij, where Ti = treatment, Bj = biopsy number, TBij is the treatment × biopsy number interaction as the fixed effects, ak = animal, and eij = random error as the random effects. The REPEATED statement was used to determine the effect of time on gene expression, and the covariance structure with the lowest BIC was used. The LSMEANS, PDIFF, and SLICE

138 statements were used to record treatment least square mean estimates, standard errors, and distinguish differences between the treatment levels. A significance of fixed effects was established at P ≤ 0.05 and tendencies are discussed at 0.05 < P ≤ 0.15.

RESULTS AND DISCUSSION

In experiment 1, 12th rib LM IMF percentage, determined by ether extraction, tended (P = 0.13) to be greater for T3 steers compared with T1 and T2 steers (12.7 vs. 9.7, 8.8 %, respectively). In experiment 2, 12th rib LM IMF percentage, was greater (P ≤ 0.01) for T5 steers compared with T1 and T4 steers (15.0 vs. 9.7, 8.2 %, respectively). Overall, steers sired by the high marbling Wagyu bull, OW Yasufuku 229Y, had a greater percentage of IMF at harvest when compared with steers from the high marbling Angus bull, GAR Sunrise, and high growth Wagyu bull, LMR Fukutsuru 729T (Jaborek et al., 2020). Gene expression results are discussed below (Figures 4-41). Adipogenic gene expression

Pre-adipocyte determination, proliferation, and the differentiation of pre-adipocytes into mature adipocytes is recognized as adipogenesis, which is regulated by a complex signaling cascade. The expression of zinc finger protein 423 (ZFP423) in mesenchymal progenitor cells is an indication of commitment to the adipose lineage; although, expression continues to increase after differentiation occurs (Gupta et al., 2010; Haung et al., 2012). Prostaglandin I2 synthase (PTGIS) in pre-adipocytes has been reported to trigger cAMP release, subsequent cAMP responsive element binding protein 1 (CREB1) activation, and lead to the eventual upregulation of early differentiation transcription factors, such as CCAAT enhancer binding protein beta (CEBPb; Aubert et al., 2000; Belmont et al., 2001) and peroxisome proliferator activated receptor delta (PPARd; Hanson et al., 2000) The upregulation of PPARd leads to mitotic expansion of pre-adipocytes and subsequent upregulation of PPARg (Hanson et al., 2000). In addition to genes associated with fatty acid transport and uptake for beta-oxidation in skeletal muscle (Holst et al., 2003). CCAAT enhancer binding protein beta and PPARd can upregulate the expression of late differentiation transcription factors, CEBPa and PPARg, for the ensuing upregulate genes associated with lipogenesis. In experiment 1, zinc finger protein 423 expression increased over time (P ≤ 0.01), with an upregulation at 331 and 442 DOA. The expression of PTGIS was greater (P ≤ 0.01) at 205 139 and 513 DOA than at 331 and 422 DOA, with no differences (P = 0.37) observed between steers in different treatments. Expression of CREB1 was greater (P ≤ 0.02) at 422 DOA and continued to increase at 513 DOA. There tended to be a treatment × biopsy number interaction (P = 0.10), where T1 steers had a greater CREB1 expression at 422 DOA compared with T3 steers. The expression of PPARd and CEBPb had significant treatment × biopsy number interactions. Instead of being down regulated, PPARd expression was sustained at a high level by T3 steers until 268 DOA (P ≤ 0.01) as compared with T1 and T2 steers. Additionally, T1 steers had a greater (P ≤ 0.01) PPARd expression compared with T2 and T3 steers at 422 DOA and greater expression than T2 steers at 513 DOA. Angus-sired steers (T1) exhibited a greater (P ≤ 0.01) CEBPb expression at 422 DOA compared with T2 and T3 steers, which may have been an indication of T1 steers beginning a bout of adipocyte differentiation earlier than T2 and T3 steers. The expression of CEBPa was near the limit of detection in the present study, but may have demonstrated a slight upregulation (P ≤ 0.01) at 422 and 513 DOA. Expression of PPARg was increasing (P ≤ 0.01) at 422 and 513 DOA, while T3 steers had a greater (P ≤ 0.04) overall mean expression compared with T1 and T2 steers. In experiment 2, ZFP423 expression demonstrated a similar pattern as in experiment 1, with an increased (P ≤ 0.01) ZFP423 expression when steer body weight reached 276 and 531 kg. The expression of PTGIS (P ≤ 0.01) was down regulated at 276 kg, but was upregulated again at 613 kg, similar to experiment 1. Expression of CREB1 exhibited a treatment × biopsy number interaction (P ≤ 0.02), where T1 steers had a greater expression at 422 DOA compared with T4 and T5 steers and T1 steers tended to have a greater expression at 331 DOA compared with T5 steers. There was a treatment × biopsy number interaction for PPARd expression (P ≤ 0.01), where T5 steers exhibited 2 times greater expression of PPARd at 400 kg, and T1 steers had a greater expression than T4 and T5 steers at 531 kg. The expression of CEBPb was upregulated (P ≤ 0.01) at 613 kg; but exhibited a similar pattern as in experiment 1, where T1 steers had a numerically (P = 0.15) greater expression at 531 kg compared with T4 and T5 steers. The expression of CEBPa was not different due to treatment or time, likely due to the low expression level. Peroxisome proliferator activated receptor gamma expression was upregulated (P ≤ 0.01) at 531 and 613 kg. However, PPARg expression tended to display a treatment × biopsy number interaction (P = 0.09), where T5 steers had a greater PPARg expression at 400 kg compared with T1 and T4 steers.

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Overall, ZFP423 expression may demonstrate an increase in pre-adipocyte commitment or adipogenic ability within the LM tissue of steers over the course of the present study. The expression of PTGIS exhibited two peaks at approximately 6.7 months of age and near harvest, at approximately 17.4 months of age. These two PTGIS peaks may represent a collection of preadipocytes beginning to differentiate in the LM of steers in the present study. The greater CREB1 expression for Angus-sired steers from approximately 12.1 to 16.8 months of age may indicate earlier differentiation of pre-adipocytes compared with Wagyu-sired steers. Expression of early differentiation markers (PPARd and CEBPb) did not necessarily peak after PTGIS expression peaked. Instead, CEBPb peaked at harvest, with Angus-sired steers having a greater expression prior to harvest compared with Wagyu-sired steers. A greater CEBPb expression for Angus-sired steers may further support the idea of earlier differentiation of pre-adipocytes compared with Wagyu-sired steers, as shown by CREB1. The expression of PPARd demonstrated multiple treatment differences over time. Peroxisome proliferator activated receptor delta expression was sustained until approximately 8.8 months of age for OW Yasufuku 229Y-sired steers in experiment 1, and a peak in PPARd expression at approximately 12.1 months of age for OW Yasufuku 229Y-sired steers in experiment 2, was different compared with Angus- and Fukutsuru-sired steers in the present study. The upregulation of PPARd in OW Yasufuku 229Y-sired steers may increased proliferation of pre-adipocytes in the LM compared with Angus- and Fukutsuru-sired steers. As a possible result of PPARd upregulation in the LM, PPARg expression was greater for OW Yasufuku 229Y-sired steers beginning at 12.1 months of age compared with steers from other treatments. The increased expression of PPARg in all steers at 422 DOA (approximately 13.8 months old) likely resulted in the transcription of other genes associated with lipogenesis at this time. Lipogenic gene expression

Lipogenesis is the process from which energy, in the form of acetyl-CoA, is used to create fatty acids and store them as triglycerides. Excess energy can lead to an excessive supply of citrate, which can be converted back to acetyl-CoA by ATP citrate lyase (ACLY) in the cytosol of the cell. For fatty acid synthesis to occur, acetyl-CoA must be converted to malonyl- CoA by acetyl-CoA carboxylase (ACAC). Fatty acid synthase (FASN) proceeds to add acetyl groups for the formation of 16 and 18 carbon long-chain fatty acids. Fatty acids can be elongated with the addition of two carbons or desaturated to include a double bond by fatty acid

141 elongase 6 (ELOVL6) and stearoyl-CoA desaturase (SCD), respectively. Sterol regulatory element binding transcription factor 1 (SREBF1) regulates fatty acid synthesis by transcribing ACLY, ACAC, and FASN. In addition, PPARg assists in the regulation of genes involved in triglyceride synthesis. In experiment 1, SREBF1 expression (P ≤ 0.01) decreased at 268 and 331 DOA, but increased again at 422 and 513 DOA for steers. Sterol regulatory element binding transcription factor 1 tended to have a treatment × biopsy number interaction (P = 0.051), where T1 steers had a numerically greater SREBF1 expression at 422 DOA compared with T2 and T3 steers. The expression of ACLY (P ≤ 0.01), ACACA (P ≤ 0.01), and FASN (P ≤ 0.01) peaked at 422 DOA for steers in experiment 1. Acetyl-CoA carboxylase alpha expression tended (P = 0.09) to be greater for T3 steers compared with T1 and T2 steers, which was driven by its numerically greater expression at 422 DOA. The expression of ELOVL6 (P ≤ 0.01) and SCD (P ≤ 0.01) were upregulated at 422 DOA and ELOVL6 (P = 0.06) and SCD (P = 0.08) tended to be greater for T3 steers compared with T1 and T2 steers. The expression of glycerol-3-phosphate dehydrogenase 1 (GPD1) was greater (P ≤ 0.01) at 268, 331, and 422 DOA, while becoming down regulated at 513 DOA. The expression of glycerol-3-phosphate acyltransferase (GPAM) exhibited a treatment × biopsy number interaction (P ≤ 0.04), where expression was greater at 331 DOA for T2 steers compared with T1 steers, and T3 steers tended to have a greater GPAM expression compared with T1 steers at 331 and 422 DOA and T2 steers at 422 DOA. The expression of 1-acylglycerol-3-phosphate O-acyltransferase 1 (AGPAT1) was slightly greater at 205 and 513 DOA, but there were no treatment differences. Phosphatidic acid phosphatase or lipin 1 (LPIN1) expression exhibited a similar pattern of expression as PPARd. A treatment × biopsy number interaction (P ≤ 0.02) for LPIN1 resulted from T3 steers tending to have a numerically greater expression at 268 DOA, while T1 steers had a greater expression at 422 DOA compared with T2 and T3 steers. Diacylglycerol O-acyltransferase 1 (DGAT1) expression was relatively constant with the greatest expression tending (P = 0.07) to be at 513 DOA. In experiment 2, SREBF1 had a treatment × biopsy number interaction (P ≤ 0.01), with T4 and T5 steers having a greater expression at 400 kg, but T1 steers had a greater expression than T4 and T5 steers at 531 kg. Similar to experiment 1, steers in experiment 2 had a greater expression of ACLY (P ≤ 0.01), ACACA (P ≤ 0.01), FASN (P ≤ 0.01), ELOVL6 (P ≤ 0.01), and SCD (P ≤ 0.01) at 531 kg. The expression pattern of GPD1 and AGPAT1 were similar to

142 experiment 1. Glycerol-3-phosphate acyltransferase expression displayed a treatment × biopsy number interaction (P ≤ 0.02), with a greater expression for T5 steers at 400 and 613 kg compared with T1 and T4 steers. Similar to experiment 1, LPIN1 exhibited a similar pattern of expression as PPARd, with a greater expression for T5 steers at 400 kg compared with T1 and T2 steers and T1 steers had a greater expression at 531 kg compared with T4 and T5 steers (treatment × biopsy number interaction, P ≤ 0.01). The expression of DGAT1 tended (P = 0.07) to be greater for T4 and T5 steers compared with T1 steers. Overall, SREBF1 expression appears to decrease slightly after 7 months of age and increase again at approximately 11.7 months of age. At approximately 13.8 months of age, Angus-sired steers had a greater SREBF1 expression compared with Wagyu-sired steers, which again, may indicate earlier differentiation and lipid filling of pre-adipocytes. Along with an increase in fatty acid synthesis, at approximately 11.7 months of age the expression of genes related to fatty acid and triglyceride synthesis began to increase and peak at approximately 13.8 months of age, and decline slightly before harvest. For OW Yasufuku 229Y-sired steers, the expression of GPAM was greater after 12.1 months of age until harvest as compared with other steers, which also closely resembles PPARg expression. Interestingly, LPIN1 expression closely resembles CEBPb and/or PPARd expression, where OW Yasufuku 229Y-sired steers exhibited greater peaks of LPIN1 expression at 8.8, 12.1, and 16.8 months of age compared with other steers. Both lysophosphatidic acid, a product of GPAM activity, and LPIN1 can promote PPARg expression, as phosphatidic acid inhibits PPARg expression (McIntyre et al., 2003; Zhang et al., 2012). Maybe it is possible early differentiation markers such as PPARd and CEBPb, help regulate the transcription of GPAM and LPIN1 to assist in the activation of PPARg transcription. Angiogenic gene expression

Adipose tissue development, particularly IMF development, appears to be spatially related to capillary proximity. Vascular endothelial growth factor (VEGF) is necessary for the formation of immature blood vessels (Hausman and Richardson, 2004). Angiopoietin 1 (ANGPT1) is responsible for vascular remodeling and capillary growth and branching, while ANGPT2 is responsible for destabilizing the structure of blood vessels and regulating ANGPT1 (Hausman and Richardson, 2004). Platelet derived growth factor beta (PDGFB) is responsible for helping to maintain capillary wall stability by the recruitment and proliferation of pericytes.

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Uezumi et al. (2010) reported that PDGFRA was a cell surface marker for identifying mesenchymal progenitor cells determined to the adipogenic lineage. Therefore, PDGFRA expression may indicate when pre-adipocytes are more abundant in the LM of steers in the present study. In experiment 1, VEGF expression was greater (P ≤ 0.01) at 205 and 268 DOA. The expression of ANGPT1 increased slightly from 205 DOA to 422 DOA, but decreased (P ≤ 0.04) afterwards. The opposite expression was exhibited for ANGPT2, where expression increased (P ≤ 0.01) until 331 DOA and remained relatively constant. Platelet derived growth factor beta expression increased (P ≤ 0.01) after 422 DOA. The expression of PDGFRA increased (P ≤ 0.01) until 331 DOA, decreased slightly, and increased again until 513 DOA. Experiment 2 demonstrated many of the same expression patterns as experiment 1. However, ANGPT1 exhibited a treatment × biopsy number interaction (P ≤ 0.02), where ANGPT1 expression was 2 times greater for T1 and T4 steers compared with T5 steers at 400 kg. In addition to the greater (P ≤ 0.02) expression of PDGFRA at 613 kg, T4 steers had a greater (P ≤ 0.01) overall mean expression compared with T1 and T5 steers. The expression of VEGF would signify vascular development occurring at 6.7 to 8.7 months of age in the LM, but decreases thereafter. Angus-sired and LMR Fukutsuru 729T-sired steers’ expression of ANGPT1 was relatively constant until decreasing at approximately 14.3 months of age. While ANGPT1 expression for OW Yasufuku 229Y-sired steers increased from 6.7 to 10.9 months of age, then decreased, and increased again from 12.1 to 13.8 months of age, before decreasing again. Wagner et al. (2009) reported that PPARd can increase cardiac muscle growth and angiogenesis. However, our results may be in disagreement, as ANGPT1 expression appeared to exhibit the opposite expression of PPARd. Although, differences may be due to muscle type (skeletal vs. with cardiac). The expression of PDGFRB increased just as ANGPT1 expression decreased, possibly to strengthen the newly branched capillaries. The expression of ANGPT2 increased slightly from 6.7 to 9.2 months of age, but demonstrated relatively constant remodeling there on after. Platelet derived growth factor alpha expression demonstrated a small peak and larger peak in expression from 9.2 to 13.8 and from 15.0 to harvest, respectively. These peaks in PDGFRA expression may reflect times of pre-adipocyte proliferation and an increase in the number of pre-adipocytes within the LM of steers. Expression of genes as potential pre-adipocyte markers (ZFP423, PTGIS, and PDGFRA) are different and all three

144 genes may not accurately identify an increase in the abundance of pre-adipocytes in the LM of steers in the present study. Further analysis needs to be conducted to confirm when preadipocyte number is increasing within the LM. Fatty acid uptake and transport gene expression

Dietary fatty acids or liver de novo fatty acids are transported through the circulatory system to other tissues, such muscle or adipose tissue for energy use or storage, by chylomicrons and lipoproteins. Lipoprotein lipase (LPL) or other lipoprotein receptors such as low density lipoprotein receptor (LDLR), hydrolyze triglycerides transported by the lipoproteins into glycerol and 3 fatty acids that can be taken up by the peripheral tissue for energy use or storage. The cd36 molecule (CD36) and solute carrier family 27 member 1 (SLC27A1) transport fatty acids into the cell, which can be bound by fatty acid transporters such as, fatty acid binding protein 4 (FABP4), diazepam binding inhibitor (DBI), and SLC27A1 for fatty acid transport within the cell. In experiment 1, LPL expression was greater (P ≤ 0.01) at 205 and 513 DOA for steers. The expression of LDLR was greater (treatment × biopsy number interaction, P ≤ 0.01) for T3 steers at 422 DOA compared to T1 and T2 steers. Unlike LPL and LDLR, scavenger receptor class B member1 (SCARB1) expression began to decrease (P ≤ 0.01) after 422 DOA for steers in the present study. The expression of CD36 was greater (P ≤ 0.01) at 513 DOA, while SLC27A1 expression was greater (treatment × biopsy number interaction, P ≤ 0.01) for T1 steers at 422 DOA compared with T2 and T3 steers. Fatty acid binding protein 4 expression was greater (P ≤ 0.01) at 422 and 513 DOA, and tended (P = 0.07) to be greater for T3 steers compared to T1 and T2 steers. The expression of DBI increased (P ≤ 0.01) rapidly after 205 DOA, and expression was greatest at 268 and 513 DOA and slightly lesser expression at 331 and 422 DOA for steers in the present experiment. The expression pattern of LPL in experiment 2 was similar to experiment 1, with a greater expression at 241 and 613 kg. Low density lipoprotein receptor expression was greater for T4 and T5 steers at 276 kg compared with T1 steers and T4 steers had a greater expression at 400 kg compared with T1 and T5 steers (treatment × biopsy number interaction, P ≤ 0.01). The expression of SCARB1 was greatest (P ≤ 0.01) at 276 kg and decreased thereafter. Similar to experiment 1, CD36 expression was greatest (P ≤ 0.01) at 613 kg and FABP4 expression was greatest (P ≤ 0.01) at 531 and 613 kg. Like experiment 1, T1 steers had a greater expression of

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SLC27A1 at 531 kg compared with T4 and T5 steers, but interestingly, T4 and T5 had a greater expression of SLC27A1 at 276 kg compared with T1 steers (treatment × biopsy number interaction, P ≤ 0.02). The expression of DBI exhibited a treatment × biopsy number interaction (P ≤ 0.05), where T4 steers had a greater expression at 276 kg compared with T1 and T5 steers. Overall, LPL expression may demonstrate a greater fatty acid uptake when steers were approximately 6.7 and 16.8 months of age. Greater LPL expression at 6.7 and 16.8 months of age may be for the mobilization of fatty acids needed for energy to initiate differentiation of preadipocytes. However, LDLR expression illustrated breed differences over time for fatty acid uptake; with Wagyu-sired steers having a greater LDLR expression at 9.3 months of age, LMR Fukutsuru 729T-sired steers having a greater LDLR expression at 11.6 months of age compared with all steers, and OW Yasufuku 229Y-sired steers having a greater LDLR expression at 13.8 months of age relative to Angus-sired steers. The upregulation of CD36 did not occur until approximately 16.8 months of age or harvest, which indicates fatty acid uptake in the steers of the present study was also controlled in some other way. Possibly by SLC27A1, which demonstrated a relatively constant expression for Wagyu-sired steers compared with the low level of expression prior to peak expression at approximately 13.8 months of age in Angus-sired steers. Therefore, Wagyu-sired steers may have a greater fatty acid uptake at a younger age (9.3 months) compared with Angus-sired steers. Fatty acid binding protein 4 expression closely resembles PPARg expression, with a large increase in expression after 11.5 months of age and a tendency for greater FABP4 expression by OW Yasufuku 229Y-sired steers. Interestingly, DBI expression demonstrated a dramatic increase once arriving to the feedlot at 8.8 months of age. Therefore, weaning steer calves from their dams and switching them to a backgrounding diet likely influenced the upregulation of DBI. Lipolytic gene expression

When energy is needed, fatty acids can be hydrolyzed from triglycerides by patatin like phospholipase domain containing 2 (PNPLA2), hormone sensitive lipase (HSL), and monoglyceride lipase (MGL). Acyl-CoA bound fatty acids can enter the mitochondria through carnitine palmitoyltransferases (CPT) to undergo beta-oxidation. Beta-oxidation is initiated by acyl-CoA dehydrogenase (ACAD) to remove acetyl-CoA units to be used for subsequent ATP production. Peroxisome proliferator activated receptor alpha regulates the transcription of genes needed for beta-oxidation.

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The expression of PPARA tended to be greater (P = 0.08) at 205 DOA compared with 331 DOA for steers in experiment 1. The expression of PPARG coactivator 1 alpha (PPARGC1A) closely resembled PPARA expression, such that PPARGC1A expression decreased (P ≤ 0.01) from 205 to 268 DOA. Expression of PNPLA2 was upregulated (P ≤ 0.01) at 205 and 513 DOA for steers. Hormone sensitive lipase expression was also greater (P ≤ 0.01) at 513 DOA, with T3 steers having a greater (P ≤ 0.04) overall mean expression compared with T1 and T2 steers. The expression of MGL was greatest (P ≤ 0.01) at 513 DOA, and T3 steers tended (P = 0.10) to have a greater MGL expression at 422 DOA compared with T1 and T2 steers. Expression of CPT1 (P ≤ 0.01) and ACADVL (P ≤ 0.01) were slightly greater at 205 DOA compared with 268, 331, and 442 DOA, while CPT1 and ACADVL expression was greatest at 513 DOA. In experiment 2, PPARA expression was greater (P ≤ 0.03) for steers at 241, 276, and 613 kg and tended to be greater (P = 0.10) for T4 steers compared with T1 and T5 steers. Expression of PPARGC1A decreased (P ≤ 0.01) after 241 kg for steers in the present study. The expression of PNPLA2 (P ≤ 0.01) and MGL (P ≤ 0.01) both displayed similar patterns of gene expression as in experiment 1; although, overall mean MGL expression was greater (P ≤ 0.01) for T5 steers compared with T1 and T4 steers. Hormone sensitive lipase expression was greater for T5 steers at 400 kg compared with T1 and T4 steers (treatment × biopsy number interaction, P ≤ 0.05). Expression of CTP1 increased (P ≤ 0.01) from 531 to 613 kg, while T5 steers tended to have a greater expression of CPT1 at 400 kg compared with T1 and T4 steers (treatment × biopsy number interaction, P = 0.10). The expression of ACADVL was greater for T5 steers compared with T1 and T4 steers at 400 kg, while T1 steers had a greater expression at 531 kg compared to T4 steers (treatment × biopsy number interaction, P ≤ 0.03). Overall, PPARA and PPARGC1A expression decreased drastically after 6.7 months of age until 10.9 months of age, before increasing again after 14.6 months of age. After 14.6 months of age the expression of genes associated with lipolysis were upregulated as seen by CPT1, ACADVL, PNPLA2, HSL, and MGL. Interestingly, OW Yasufuku 229Y-sired steers had a greater overall expression of HSL compared with other steers, but had the greatest amount of marbling deposition. Oxidative gene expression has been reported to increase to provide energy needed for pre-adipocyte differentiation. Additionally, the upregulation of oxidative genes coincides with the upregulation of lipogenic genes as steers matured, which may indicate

147 the initiation of another adipogenic wave cycle. Possibly demonstrating that as mature adipocyte were filled, additional pre-adipocytes were needed to undergo differentiation for the IMF depot to continue to store the excess energy as lipid. Implications

In conclusion, pre-adipocytes in the LM of steers may be initiating differentiation at 7 and 17 months of age. Gene expression results may indicate that blood vessel development decreased after 8 months of age; however, vascular branching continued until approximately 15 to 16 months of age. The expression of the master regulator of adipogenesis, PPARG, continued to increase after 11 months of age and was greater in OW Yasufuku 229Y-sired steers, which had the greatest percentage of IMF in the LM. The upregulation of lipogenic genes occurred after 12 months of age and peaked at 14 months of age. Shortly after 14 months of age, the expression of lipolytic genes increased around the age of harvest, possibly for energy mobilization needed for additional pre-adipocytes to undergo differentiation. Feeding strategies may be developed to increase energy availability during important times in intramuscular adipocyte development, while energy restriction could be used at other times to reduced overall feed costs during the finishing period in the feedlot.

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Table 21. Composition (%) of diets offered during the experiment on a dry matter basis Growing Finishing Ingredient Whole shelled corn 17.50 55.00 DDGS 17.50 10.00 Corn silage 55.00 25.00 Supplement 10.00 10.00 Ground corn 1.12 1.51 Soybean meal 5.00 5.00 Digest More 1 0.78 0.39 Limestone 1.10 1.10 White salt 1.00 1.00 Urea 0.50 0.50 Vit. A, 30,000 IU/g 0.00 0.00 Vit. D, 3,000 IU/g 0.01 0.01 Vit. E, 44 IU/g 0.02 0.02 Selenium, 201 ppm 0.14 0.14 Potassium Chloride 0.30 0.30 Copper Sulfate 0.01 0.01 Zinc Sulfate 0.02 0.02 Magnesium Sulfate 0.01 0.01

Analyzed composition Crude protein, % 14.22 12.90 NDF, % 28.18 17.09 Fat, % 3.71 3.59 Ca, % 0.52 0.45 P, % 0.35 0.33 NEm, Mcal/kg 2.01 2.21 NEg, Mcal/kg 1.35 1.52 1 Amaferm (BioZyme, St. Joesph, MO)

151

Table 22. List of genes analyzed from longissimus muscle tissue of Angus- and Wagyu- sired steers Gene Accession abbreviation Gene name number ACACA acetyl-CoA carboxylase alpha NM_174224.2 ACACB acetyl-CoA carboxylase beta NM_001205333.1 ACADVL acyl-CoA dehydrogenase very long chain NM_174494.2 ACLY ATP citrate lyase NM_001037457.1 AGPAT1 1-acylglycerol-3-phosphate O-acyltransferase 1 NM_177518.1 ANGPT1 angiopoietin 1 NM_001076797.1 ANGPT2 angiopoietin 2 NM_001098855.1 CD36 cd36 molecule (thrombospondin receptor) NM_174010.2 CEBPA CCAAT enhancer binding protein alpha NM_176784.2 CEBPB CCAAT enhancer binding protein beta NM_176788.1 CPT1A carnitine palmitoyltransferase 1A NM_001304989.2 CREB1 cAMP responsive element binding protein 1 NM_174285.1 DBI diazepam binding inhibitor NM_001113321.1 DGAT1 diacylglycerol O-acyltransferase 1 NM_174693.2 DLK1 delta like non-canonical Notch ligand 1 NM_174037.2 ELOVL6 fatty acid elongase 6 NM_001102155.1 FABP4 fatty acid binding protein 4 NM_174314.2 FASN fatty acid synthase NM_001012669.1 FBLN1 fibulin 1 NM_001098029.1 GPAM glycerol-3-phosphate acyltransferase NM_001012282.1 GPD1 glycerol-3-phosphate dehydrogenase 1 NM_001035354.1 LDLR low density lipoprotein receptor NM_001166530.1 LIPE lipase E, hormone sensitive type NM_001080220.1 LPIN1 lipin 1 NM_001206156.2 LPL lipoprotein lipase NM_001075120.1 MGL monoglyceride lipase NM_001206681.1 OLR1 oxidized low density lipoprotein receptor 1 NM_174132.2 PDGFRA platelet-derived growth factor receptor alpha NM_001192345.1 PDGFRB platelet-derived growth factor receptor beta NM_001075896.2 PNPLA2 patatin like phospholipase domain containing 2 NM_001046005.2 PPARA peroxisome proliferator activated receptor alpha NM_001034036.1 PPARD peroxisome proliferator activated receptor delta NM_001083636.1 PPARG peroxisome proliferator activated receptor gamma NM_181024.2 PPARGC1A PPARG coactivator 1 alpha NM_177945.3

Continued

152

Table 22. Continued

PTGIS prostaglandin I2 synthase NM_174444.1 PTGIS1 prostaglandin-endoperoxide synthase 1 NM_001105323.1 PTGIS2 prostaglandin-endoperoxide synthase 2 NM_174445.2 SCARB1 scavenger receptor class B member 1 NM_174597.2 SCD stearoyl-CoA desaturase NM_173959.4 SLC27A1 solute carrier family 27 member 1 NM_001033625.2 SREBF1 sterol regulatory element binding transcription factor 1 NM_001113302.1 VEGFA vascular endothelial growth factor A NM_174216.2 ZFP423 zinc finger protein 423 NM_001101893.1 ACTB actin beta NM_173979.3 EEF1A2 eukaryotic translation elongation factor 1 alpha 2 NM_001037464.1 HPRT1 hypoxanthine phosphoribosyltransferase 1 NM_001034035.1 PPIA peptidylprolyl isomerase A NM_178320.2 PPP1CA protein phosphatase 1 catalytic subunit alpha NM_001035316.2 SDHA succinate dehydrogenase complex flavoprotein subunit A NM_174178.2

153

ZFP423 DOF TRT = 0.70 BN = 0.01 TRT×BN = 0.78 250 c c b a a 200

150

100 Relative Expression Relative 50 200 250 300 350 400 450 500 Days of age (d)

ZFP423 BW TRT = 0.42 BN = 0.01 TRT×BN = 0.21 250 c b b a a 200

150

100 Relative Expression Relative 50 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 4. Expression of zinc finger protein 423 (ZFP423) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

154

PTGIS DOF TRT = 0.37 BN = 0.01 TRT×BN = 0.44 100 a ab bc c a 80

40 Relative Expression Relative 20 200 250 300 350 400 450 500 Age (d)

PTGIS BW TRT = 0.22 BN = 0.01 TRT×BN = 0.20 100 a b b b a 80

40 Relative Expression Relative 20 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 5. Expression of prostacyclin synthase (PTGIS) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

155

CREB1 DOF TRT = 0.43 BN = 0.02 TRT×BN = 0.10 110 100 90 80 70

60 Relative Expression Relative 50 200 250 300 350 400 450 500 Age (d) 1 2 3

CREB1 BW TRT = 0.06 BN = 0.11 TRT×BN = 0.02 110  100 90 80 70

60 Relative Expression Relative 50 200 250 300 350 400 450 500 550 600 Body weight (kg) 1 4 5

Figure 6. Expression of cAMP responsive element binding protein 1 (CREB1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05).

156

CEBPb DOF TRT = 0.64 BN = 0.01 TRT×BN = 0.01 1400  1200 1000 800

600 Relative Expression Relative 400 200 250 300 350 400 450 500 550 Age (d) 1 2 3

CEBPb BW TRT = 0.72 BN = 0.01 TRT×BN = 0.15 1400 b b b b a 1200 1000 800

600 Relative Expression Relative 400 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 7. Expression of CCAAT enhancer binding protein beta (CEBPb) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

157

PPARd DOF TRT = 0.09 BN = 0.01 TRT×BN = 0.02 100    80 60 40

20 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d) 1 2 3

PPARd BW TRT = 0.73 BN = 0.01 TRT×BN = 0.01 100   80 60 40 20 Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg) 1 4 5

Figure 8. Expression of peroxisome proliferator activated receptor delta (PPARd) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05).

158

CEBPa DOF TRT = 0.15 BN = 0.01 TRT×BN = 0.36 50 b bc c a ab 40 30 20

10 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d)

Figure 9. Expression of CCAAT enhancer binding protein alpha (CEBPa) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

159

PPARg DOF TRT = 0.04 BN = 0.01 TRT×BN = 0.46 100 bc c bc a a 80 60 40

20 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d)

PPARg BW TRT = 0.09 BN = 0.01 TRT×BN = 0.09 100 80 60 40 20

Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg) 1 4 5

Figure 10. Expression of peroxisome proliferator activated receptor gamma (PPARg) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05).

160

SREBF1 DOF TRT = 0.60 BN = 0.01 TRT×BN = 0.06 120 100 80 60 40

20 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d) 1 2 3

SREBF1 BW TRT = 0.89 BN = 0.01 TRT×BN = 0.01 120   100 80 60 40

20 Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg) 1 4 5

Figure 11. Expression of sterol regulatory element binding transcription factor 1 (SREBF1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05).

161

ACLY DOF TRT = 0.18 BN = 0.01 TRT×BN = 0.79 200 d cd bc a bc 150

100

50 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d)

ACLY BW TRT = 0.96 BN = 0.01 TRT×BN = 0.96 200 d c ab a bc 150

100

50 Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 12. Expression of ATP citrate lyase (ACLY) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

162

ACAC1 DOF TRT = 0.09 BN = 0.01 TRT×BN = 0.63 200 c c bc a ab 150

100

50 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d)

ACAC1 BW TRT = 0.43 BN = 0.01 TRT×BN = 0.66 200 c c b a ab 150

100

50 Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 13. Expression of acetyl-CoA carboxylase 1 (ACAC1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

163

ACAC2 DOF TRT = 0.89 BN = 0.01 TRT×BN = 0.04 1000  800

600

400 Relative Expression Relative 200 200 250 300 350 400 450 500 Age (d) 1 2 3

ACAC2 BW TRT = 0.85 BN = 0.01 TRT×BN = 0.01 1000 *  800

600

400

Relative Expression Relative 200 200 250 300 350 400 450 500 550 600 Body weight (kg) 1 4 5

Figure 14. Expression of acetyl-CoA carboxylase 2 (ACAC2) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05).

164

FASN DOF TRT = 0.19 BN = 0.01 TRT×BN = 0.87

c bc b a ab 1600

1200

800

400 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d)

FASN BW TRT = 0.48 BN = 0.01 TRT×BN = 0.86

b b a a a 1600

1200

800

400 Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 15. Expression of fatty acid synthase (FASN) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

165

ELOVL6 DOF TRT = 0.06 BN = 0.01 TRT×BN = 0.54 400 c bc b a b 300

200

100 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d)

ELOVL6 BW TRT = 0.19 BN = 0.01 TRT×BN = 0.62 400 c c b a ab 300

200

100 Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 16. Expression of fatty acid elongase 6 (ELOVL6) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

166

SCD DOF TRT = 0.08 BN = 0.01 TRT×BN = 0.40 5000 c c bc a ab 4000 3000 2000

1000 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d)

SCD BW TRT = 0.28 BN = 0.01 TRT×BN = 0.59 5000 c c b a ab 4000 3000 2000

1000 Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 17. Expression of stearoyl-CoA desaturase (SCD) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

167

GPD1 DOF TRT = 0.85 BN = 0.01 TRT×BN = 0.36 5000 b a a a c 4250

3500

2750 Relative Expression Relative 2000 200 250 300 350 400 450 500 Age (d)

GPD1 BW TRT = 0.38 BN = 0.01 TRT×BN = 0.27 5000 b a a a c 4250

3500

2750 Relative Expression Relative 2000 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 18. Expression of glycerol-3-phosphate dehydrogenase 1 (GPD1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

168

GPAM DOF TRT = 0.04 BN = 0.01 TRT×BN = 0.04 400  300

200

100

Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d) 1 2 3

GPAM BW TRT = 0.02 BN = 0.01 TRT×BN = 0.02 400   300

200

100

Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg) 1 4 5

Figure 19. Expression of glycerol-3-phosphate acyltransferase (GPAM) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05).

169

AGPAT1 DOF TRT = 0.47 BN = 0.02 TRT×BN = 0.86 80 a ab b b a 60

20 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d)

AGPAT1 BW TRT = 0.87 BN = 0.02 TRT×BN = 0.59 80 ab c c bc a 60

20 Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 20. Expression of 1-acylglycerol-3-phosphate O-acyltransferase 1 (AGPAT1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

170

LPIN1 DOF TRT = 0.28 BN = 0.01 TRT×BN = 0.02

6000  5000 4000 3000 2000 1000 Relative Expression Relative 0 200 300 400 500 Age (d) 1 2 3

LPIN1 BW TRT = 0.93 BN = 0.01 TRT×BN = 0.01

6000  5000  4000 3000 2000 1000 Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg) 1 4 5

Figure 21. Expression of lipin 1 (LPIN1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05).

171

DGAT1 DOF TRT = 0.18 BN = 0.07 TRT×BN = 0.91 50 40 30 20

10 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d)

Figure 22. Expression of diacylglycerol O-acyltransferase 1 (DGAT1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

172

VEGF DOF TRT = 0.46 BN = 0.01 TRT×BN = 0.62 450 ab a d bc cd 400 350 300 250

200 Relative Expression Relative 150 200 250 300 350 400 450 500 Age (d)

VEGF BW TRT = 0.57 BN = 0.07 TRT×BN = 0.15 450 400 350 300 250

200 Relative Expression Relative 150 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 23. Expression of vascular endothelial growth factor (VEGF) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

173

ANGPT1 DOF TRT = 0.61 BN = 0.04 TRT×BN = 0.40 80 ab ab a a b 60

20 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d)

ANGPT1 BW TRT = 0.32 BN = 0.01 TRT×BN = 0.02 80  60

Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg) 1 4 5

Figure 24. Expression of angiopoietin 1 (ANGPT1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05).

174

ANGPT2 DOF TRT = 0.68 BN = 0.01 TRT×BN = 0.38 60 c b ab a ab 50 40 30 20

10 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d)

ANGPT2 BW TRT = 0.56 BN = 0.01 TRT×BN = 0.42 60 b a a a a 50 40 30 20

10 Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 25. Expression of angiopoietin 2 (ANGPT2) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

175

PDGFRa DOF TRT = 0.72 BN = 0.01 TRT×BN = 0.79 300 c bc ab bc a 250

200

150 Relative Expression Relative 100 200 250 300 350 400 450 500 Age (d)

PDGFRa BW TRT = 0.01 BN = 0.02 TRT×BN = 0.31 300 b b ab b a 250

200

150 Relative Expression Relative 100 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 26. Expression of platelet derived growth factor alpha (PDGFA) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

176

PDGFRb DOF TRT = 0.33 BN = 0.01 TRT×BN = 0.52 300 b b b b a

250

200 Relative Expression Relative 150 200 250 300 350 400 450 500 Age (d)

Figure 27. Expression of platelet derived growth factor beta (PDGFB) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

177

LPL DOF TRT = 0.21 BN = 0.01 TRT×BN = 0.22 1400 a b b b a 1200 1000 800

600 Relative Expression Relative 400 200 250 300 350 400 450 500 Age (d)

LPL BW TRT = 0.13 BN = 0.01 TRT×BN = 0.68 1400 a c c bc ab 1200 1000 800

600 Relative Expression Relative 400 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 28. Expression of lipoprotein lipase (LPL) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

178

LDLR DOF TRT = 0.08 BN = 0.01 TRT×BN = 0.01 125  100 75 50

25 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d) 1 2 3

LDLR BW TRT = 0.01 BN = 0.01 TRT×BN = 0.01 125   100 75 50

25 Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg) 1 4 5

Figure 29. Expression of low density lipoprotein receptor (LDLR) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05).

179

SCARB1 DOF TRT = 0.07 BN = 0.01 TRT×BN = 0.30 100 ab a ab b c 80 60 40

20 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d)

SCARB1 BW TRT = 0.06 BN = 0.01 TRT×BN = 0.16 100 b a b bc c 80 60 40

20 Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 30. Expression of scavenger receptor class B member1 (SCARB1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

180

CD36 DOF TRT = 0.11 BN = 0.01 TRT×BN = 0.35 4000 a b b b b

3000

2000 Relative Expression Relative 1000 200 250 300 350 400 450 500 Age (d)

CD36 BW TRT = 0.03 BN = 0.01 TRT×BN = 0.68 4000 b b b b a

3000

2000 Relative Expression Relative 1000 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 31. Expression of cd36 molecule (CD36) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

181

SLC27A1 DOF TRT = 0.55 BN = 0.01 TRT×BN = 0.01 250 

200

150 Relative Expression Relative 100 200 250 300 350 400 450 500 Age (d) 1 2 3

SLC27A1 BW TRT= 0.18 BN = 0.12 TRT×BN = 0.02 250 

200

150 Relative Expression Relative 100 200 250 300 350 400 450 500 550 600 Body weight (kg) 1 4 5

Figure 32. Expression of solute carrier family 27 member 1 (SLC27A1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates between treatment 1 (■), treatment 2 (●), and treatment 3 (○) steers at a given biopsy with a () differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05).

182

FABP4 DOF TRT = 0.07 BN = 0.04 TRT×BN = 0.43 3000 a b b b a 2500 2000 1500 1000

500 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d)

FABP4 BW TRT = 0.53 BN = 0.01 TRT×BN = 0.85 3000 bc d c ab a 2500 2000 1500 1000

500 Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg)

183

DBI DOF TRT = 0.40 BN = 0.01 TRT×BN = 0.47 5000 d ab c bc a 4000

3000

2000 Relative Expression Relative 1000 200 250 300 350 400 450 500 Days of age (d)

DBI BW TRT = 0.06 BN = 0.01 TRT×BN = 0.05 5000  4000

3000

2000 Relative Expression Relative 1000 200 250 300 350 400 450 500 550 600 Body weight (kg) 1 4 5

Figure 34. Expression of diazepam binding inhibitor (DBI) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05).

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PPARa DOF TRT = 0.53 BN = 0.08 TRT×BN = 0.97 800

700

600

500 Relative Expression Relative 400 200 250 300 350 400 450 500 Age (d)

PPARa BW TRT = 0.10 BN = 0.03 TRT×BN = 0.63 800 a a b b ab 700

600

500 Relative Expression Relative 400 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 35. Expression of peroxisome proliferator activated receptor alpha (PPARA) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

185

PPARGC1a DOF TRT = 0.71 BN = 0.01 TRT×BN = 0.36 350 a b d cd bc 300 250 200

150 Relative Expression Relative 100 200 250 300 350 400 450 500 Age (d)

PPARGC1a BW TRT = 0.93 BN = 0.01 TRT×BN = 0.34 350 a ab bcd d c 300 250 200

150 Relative Expression Relative 100 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 36. Expression of peroxisome proliferator activated receptor coactivator 1 alpha (PPARGC1A) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

186

PNPLA2 DOF TRT = 0.72 BN = 0.01 TRT×BN = 0.71 1750 a bc c b a 1500 1250 1000

750 Relative Expression Relative 500 200 250 300 350 400 450 500 Age (d)

PNPLA2 BW TRT = 0.18 BN = 0.01 TRT×BN = 0.19 1750 a b c b a 1500 1250 1000

750 Relative Expression Relative 500 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 37. Expression of patatin like phospholipase domain containing 2 (PNPLA2) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05).

187

HSL DOF TRT = 0.04 BN = 0.01 TRT×BN = 0.47 120 b bc c b a 100 80 60 40

20 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d)

HSL BW TRT = 0.13 BN = 0.01 TRT×BN = 0.05 120  100 80 60 40

20 Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg) 1 4 5

Figure 38. Expression of hormone sensitive lipase (HSL) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05).

188

MGL BW TRT = 0.51 BN = 0.01 TRT×BN = 0.10 50 b c bc b a 40 30 20

10 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d)

MGL BW TRT = 0.01 BN = 0.01 TRT×BN = 0.52 50 b b b b a 40 30 20

10 Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 39. Expression of monoglyceride lipase (MGL) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05).

189

CPT1 DOF TRT = 0.93 BN = 0.01 TRT×BN = 0.67 75 b c c c a

25 Relative Expression Relative 0 200 250 300 350 400 450 500 Age (d)

CPT1 BW TRT = 0.57 BN = 0.01 TRT×BN = 0.10 75 b c c c a

25 Relative Expression Relative 0 200 250 300 350 400 450 500 550 600 Body weight (kg)

Figure 40. Expression of carnitine palmitoyltransferases 1 (CPT1) in the longissimus muscle of steers compared at a similar days on feed (DOF; 205, 268, 331, 422, 513 days of age) or at a similar body weight (BW; 241, 296, 400, 531, 613 kg). LSmean estimates across biopsy number (BN) with different superscripts differ (P ≤ 0.05). LSmean estimates between treatment 1 (■), treatment 4 (●), and treatment 5 (○) steers at a given biopsy with a () differ (P ≤ 0.05).

190

ACADVL DOF TRT = 0.93 BN = 0.01 TRT×BN = 0.67 1250 b cd d c a 1000

750

500 Relative Expression Relative 250 200 250 300 350 400 450 500 Age (d)

ACADVL BW TRT = 0.57 BN = 0.01 TRT×BN = 0.10 1250   1000

750

500 Relative Expression Relative 250 200 250 300 350 400 450 500 550 600 Body weight (kg) 1 4 5

191

Chapter 8. Conclusion

In conclusion, this research has focused on adding value to feedlot cattle, with additional interest being directed towards increasing the understanding of marbling development and growth in cattle. Cattle are valued on a weight basis, however, carcass grid based pricing systems allow for cattle to be priced based on indicators of retail yield and meat quality. As previously mentioned, the USDA can award beef carcasses a YG indicative of the retail yield, and a QG indicative of eating satisfaction (USDA, 2016). Furthermore, additional value may be captured if products are sold into niche markets or meet labeling claims that appeal to the customer’s desires. In study 1 (Chapters 3, 4, and 5), a crossbreeding strategy was implemented with Jersey dairy cows to add value to the male offspring. Purebred Jersey steers in the study confirmed some of the challenges and benefits associated with raising purebred Jersey steers in the feedlot for beef. Conversely, crossbred Jersey steers, produced from Angus, SimAngus, and Red Wagyu sires, resulted in an increased animal value. Crossbred Jersey cattle had a greater ADG and lesser G:F compared with purebred Jersey steers. As a result of the lesser ADG of purebred Jersey steers, they required the greatest amount of time on feed. Constraints of the study caused purebred Jersey steers to be harvested at a numerically lesser off-test body weight, which contributed to a lighter hot carcass weight compared with crossbred Jersey cattle. The lesser hot carcass weight of purebred Jersey steers, resulted in 20% of the purebred Jersey carcasses receiving a discount for being under 273 kg. Purebred Jersey cattle had a lesser backfat thickness, but deposited a greater percentage of kidney fat compared with crossbred Jersey steers. Additionally, crossbred Jersey cattle had greater marbling scores and USDA quality grades compared with purebred Jersey steers. Wagyu and SimAngus sired cattle had a greater carcass retail yield compared to purebred Jersey steers. Therefore, crossbred Jersey cattle had a

192 greater boxed beef price and boxed beef value compared with purebred Jersey steers. However, as shown in Chapter 5, the USDA YG equation does a poor job predicting the carcass cutability of Jersey influenced cattle and all Jersey influenced cattle in this study had a much lesser carcass retail yield compared with conventional beef cattle. Therefore, sire selection criteria should be focus on retail yield and producers feeding Jersey influenced cattle should consider the use of growth enhancing technologies to increase muscling further. A greater boxed beef value for crossbred cattle compared with purebred Jersey steers implies a greater calf price for crossbred Jersey cattle compared with purebred Jersey cattle. Additionally, this research indicates that Jersey influenced cattle produce a very tender beef product with a desirable fatty acid composition. These meat quality characteristics further increase the ability to market Jersey influenced beef into niche markets where labeling claims appeal to the consumer’s desire for high quality beef. Overall, crossbred Jersey cattle have an increased feedlot performance, carcass cutability, carcass quality, and economic value compared with purebred Jersey steers. The second study was designed to further investigate marbling development in cattle. Marbling development or accumulation can be impacted by a variety of factors including: genetics/breed, animal age at the initiation of feeding/finishing, animal age at harvest, body weight at harvest, diet composition, health, etc. In the second study (Chapters 6 and 7), Wagyu and Angus sired cattle were compared at a similar age and days spent on feed or at a similar body weight endpoint to compare feedlot performance, carcass composition, and the expression of marbling related genes. Two Wagyu sires were used in this study, one selected for growth (LMR Fukutsuru 729T) and the other selected for marbling ability (OW Yasufuku 229Y). When compared at a similar age or days spent on feed, Angus sired cattle had a greater ADG, DMI, and G:F compared with Yasufuku sired cattle, while Fukutsuru sired cattle were similar to Angus sired cattle, except for having a lesser DMI. Therefore, after a similar number of days spent on feed, Angus sired and Fukutsuru sired cattle had a greater off-test weight. Wagyu sired cattle had a greater estimated percentage of KPH, while Yasufuku sired cattle had a greater marbling score and USDA QG compared with Angus sired cattle at a similar age and

193 days spent on feed. When compared at a similar off-test body weight, Angus sired cattle had a greater ADG, DMI, and G:F, while having spent fewer days on feed, being younger at harvest, and having a lesser total DMI over the course of the entire study. Yasufuku sired cattle had a greater marbling score, USDA QG, and 6th rib fat thickness compared to Angus sired and Fukutsuru sired cattle. At both endpoint comparisons, Yasufuku sired cattle had a longissimus muscle fatty acid composition that was more desirable compared with Angus sired cattle, while Fukutsuru sired cattle were typically intermediate. Interestingly, the additional time Wagyu sired cattle spent on feed to reach a similar off- test body weight as Angus sired cattle, did not result in a greater marbling score when compared with Wagyu sired cattle compared to Angus sired cattle at a similar age or days on feed. Therefore, marbling accumulation for cattle in the present study may have reached a plateau at the time of harvest (approximately 17 to 18 months of age). Previous reports regarding marbling deposition have demonstrated that marbling accumulates in a stair-step fashion over time (Zinn et al. 1970). Gene expression may indicate periods of pre-adipocyte proliferation and lipid filling for steers in the present study, with two critical windows at approximately 7 and 17 months of age for marbling development. Genes responsible for vascular development and growth indicate increased blood vessel development around 7 to 8 months of age and increased vascular branching continuing to occur until 15 to 16 months of age. The upregulation of lipogenic genes occurred began around 12 months of age and peaked at 14 months of age, while lipolytic genes expression was upregulated at 7 and 17 months of age. The gene expression of Yasufuku sired cattle exhibited random peaks that may indicate increased pre-adipocyte proliferation compared to Angus and Fukutsuru sired cattle. Future research can be conducted to develop feeding strategies to increase energy availability during critical marbling development times (7 and 17 months of age), while a restricted energy intake during other times may allow producers to reduce feed costs while cattle deposit similar amounts of marbling. Future research should also consider how different cattle breeds and management may shift the developmental progression of marbling in cattle.

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