Feedlot Cattle Performance When Fed Silage and Grain From Second-Generation Insect Protected Corn, Parental Line or Reference Hybrids Barry M. Weber compare the performance and carcass (34.2% DM ± 2.1%) and stored in silo Brandon L. Nuttelman characteristics of finishing steers fed bags by hybrid. Corn was stored in William A. Griffin second generation insect-protected bins by hybrid prior to dry rolling, at Josh R. Benton (Bt) corn (MON 89034) and corn which time the hybrids were stored Galen E. Erickson silage with the nontransgenic paren- in separate commodity bays. Samples Terry J. Klopfenstein1 tal hybrid (DKC 63-78) and the two of all hybrids were collected and sent nontransgenic reference hybrids (DKC to Monsanto Company where the 61-42 and DKC 62-30). presence or absence of the genes was Summary verified. Procedure Steers were adjusted to the final Feed conversion and carcass charac- diet over 21 days, with ground alfalfa teristics of cattle fed second generation Animals hay replacing corn. Alfalfa hay levels insect-protected (Bt) corn and corn were decreased from 37.5%, 27.5%, silage was compared to those fed a British x Continental crossbred 17.5%, and 7.5% for 3, 4, 7, and 7 nontransgenic parental hybrid and two steers (initial BW = 639 ± 31 lb) were days. Final diets are shown in Table commercially available nontransgenic used in a randomized complete block 1 and contained 65.0% DRC, 15.0% reference hybrids. Finishing performance design experiment. Steers (n = 240) corn silage, 15.0% WDGS, and 5.0% and carcass characteristics were not in- were received at the University of supplement. fluenced as a result of corn source. Nebraska Agricultural Research and Prior to initiation of the study, Development Center (Ithaca, Neb.) samples of corn and corn silage were Introduction in the fall of 2009. On arrival, steers collected and sent to a commercial were weighed, vaccinated (Bovishield laboratory (Romer Labs, Union, Mo.) Insect-protected corn hybrids (Bt) Gold 5, Somubac, Dectomax), and to test for the presence of mycotoxins. made up 63% of the total corn acres in treated with Micotil (Elanco Animal Small amounts of Zearalenone and 2009, according to the United States Health). Following a 14-21 day receiv- Deoxynivalenol (Vomitoxin) were Department of Agriculture’s Econom- ing period, steers were limit fed five found in the test hybrid (MON) and ic Research Service. Monsanto has days to minimize variation in rumen the nontransgenic parental hybrid developed MON 89034 as a second fill. The limit fed ration contained a (PAR) corn silage. Small amounts of generation insect protection product 1:1 ratio of wet corn gluten feed and Deoxynivalenol were also detected in to provide enhanced benefits for the alfalfa hay fed at 2% BW. Steers were all samples of whole corn, as well as control of lepidopteran insect pests. weighed individually on two consecu- Zearalenone and Fumonisin B1 and MON 89034 produces Cry1A.105 and tive days in the morning before feed- B2 in DKC 62-30 (REF2). In all sam- Cry2Ab2 proteins derived from Ba- ing to obtain an accurate initial BW. ples, the levels of mycotoxins detected cillus thuringiensis, which are active Steers were blocked by BW, stratified were well below the level of concern. against Ostrinia species such as Euro- within block, and assigned randomly Ingredient and diet samples were col- pean corn borer and Asian corn borer, to pens (10 steers/pen) based on day 0 lected weekly, composited by month, Diatraea species such as southwestern BW. Pens were assigned randomly to and sent to a commercial laboratory corn borer and sugarcane borer, and one of four treatments. (Dairy One, Ithaca, N.Y.) for nutrient helps control fall armyworm and corn analysis. earworm. Since the mode of action of Treatments Individual BW was collected on Cry1A.105 and Cry2Ab2 are different, day 0 and day 1 of the trial. Steers the combination of the two proteins Treatments consisted of two refer- were implanted with Revalor-IS on provides a much more effective insect ence hybrids, a genetically related day 1 and reimplanted with Revalor-S resistance management tool. With a nontransgenic hybrid, and the second on day 84. All steers were slaughtered high percentage of the corn being fed generation Bt hybrid (MON 89034). on day 175 at Greater Omaha (Oma- directly to cattle in feedlots, it is vital All corn was grown at the Agricul- ha, Neb.). Hot carcass weight (HCW) for producers to know if cattle fed tural Research and Development Cen- and liver abscess data were recorded MON 89034 will perform similarly to ter near Ithaca, Neb. under identity on the day of slaughter. After a 48- cattle fed nontransgenic hybrids. preserved methods. All hybrids were hour chill, USDA marbling score, 12th The objective of this study was to cut for silage at similar moisture levels rib fat thickness, and LM area were Page 76 — 2011 Nebraska Beef Cattle Report © The Board of Regents of the University of Nebraska. All rights reserved. Table 1. Diet ingredient and nutrient composition (% DM). Institute , Cary, N.C.). Pens were the Ingredient1 MON PAR REF1 REF2 experimental unit (6/treatment). Block was treated as a fixed effect in Corn W 65.0 Corn X 65.0 the model. Only 1 replication was Corn Y 65.0 included in heavy block, with 5 rep- Corn Z 65.0 lications in the other weight block. Corn Silage W 15.0 Therefore, data were analyzed and Corn Silage X 15.0 Corn Silage Y 15.0 statistics are based on this analysis. Corn Silage Z 15.0 However, least square means are not WDGS 15.0 15.0 15.0 15.0 presented due to adjustment for un- Supplement equal replication of blocks. Arithme- Fine Ground Milo 2.300 2.300 2.300 2.300 tic means are presented by treatment. Limestone 1.681 1.681 1.681 1.681 Salt 0.300 0.300 0.300 0.300 The study was blind to feedlot Urea 0.400 0.400 0.400 0.400 personnel. Each hybrid was assigned Potassium Chloride 0.099 0.099 0.099 0.099 a letter before beginning the trial. All Tallow 0.125 0.125 0.125 0.125 treatments, silage bags, commodity Trace Mineral 0.050 0.050 0.050 0.050 Vitamin A-D-E 0.015 0.015 0.015 0.015 bays, pen assignments, feed sheets, Rumensin-80 0.019 0.019 0.019 0.019 and observation documents were Tylan-40 0.011 0.011 0.011 0.011 designated by letter to limit possible Nutrient Composition partiality to treatment. CP 13.4 13.3 12.3 13.6 NDF 15.5 16.6 14.9 16.5 Ca 0.58 0.64 0.56 0.62 Results P 0.35 0.36 0.32 0.36 K 0.53 0.56 0.55 0.58 Performance and carcass data 1REF1 = reference hybrid DKC 61-42, REF2 = reference hybrid DKC 62-30, PAR = nontransgenic are shown in Table 2. No significant parental hybrid, MON = corn and corn silage containing Cry1A.105 and Cry2Ab2 proteins (MON differences in ADG, F:G, or carcass 89034). characteristics were observed among Table 2. Animal performance1. treatments. Due to a statistical differ- ence in initial BW (3 lb difference), Variable MON 89034 Parental Reference 1 Reference 2 P-value initial BW was used as a covariate of Performance analysis and unadjusted treatment Initial BW, lb 638 640 637 639 0.02 means are reported. The average Final BW, lb2 1294 1290 1293 1287 0.94 DMI, lb/day 22.3 22.6 21.9 22.5 0.96 across all treatments for ADG and F:G ADG, lb 3.74 3.71 3.75 3.70 0.31 were 3.73 and 6.00, respectively. Steers Feed:Gain3 5.97 6.09 5.85 6.07 0.13 fed MON and REF1 had numerically Carcass Characteristics better F:G ratios, with a tendency HCW, lb 815 813 815 811 0.93 Marbling score4 573 561 581 565 0.55 (P = 0.13) for more efficient feed con- 12th rib fat, in 0.51 0.49 0.53 0.52 0.82 version in steers fed REF1. LM area, in² 13.0 13.1 13.0 12.9 0.70 The source of corn, whether trans- 5 Calculated YG 3.21 3.13 3.24 3.22 0.78 genic or nontransgenic, had no sig- % Choice 79.6 71.7 74.1 68.3 0.41 nificant effect on the performance or 1REF1 = reference hybrid DKC 61-42, REF2 = reference hybrid DKC 62-30, PAR = nontransgenic carcass characteristics of the cattle in parental hybrid, MON = corn rootworm resistant hybrid MON 89034. this trial. These data indicate perfor- 2Final weight calculated as hot carcass weight divided by 0.63. 3Analyzed as gain:feed, reported as feed:gain. mance and carcass characteristics of 4500 = Small 0, 600 = Modest 0. cattle fed MON 89034 were not dif- 5YG calculation = 2.50 + (2.5 * 12th rib fat thickness) – (.32 * LM area) + (.2 * KPH (2.5)) + (.0038 * ferent from cattle fed nontransgenic HCW). corn. MON 89034 is nutritionally equivalent to nontransgenic corn. collected. Hot carcass weights were treatment (MON) and one from DKC used to calculate adjusted final BW by 61-42 (REF1) treatment died from dividing HCW by a common dress- non-treatment related illnesses during 1Barry M. Weber, graduate student; ing percentage of 63%. Average daily the trial. One steer from REF1 was re- Brandon L. Nuttelman, research technician; gain and G:F were determined from moved from the study for a reason not William A.