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ABSTRACT DYSART, NIKHOL ELIZABETH. Effect of Birth Weight

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ABSTRACT DYSART, NIKHOL ELIZABETH. Effect of Birth Weight ABSTRACT DYSART, NIKHOL ELIZABETH. Effect of Birth Weight and Human Socialization on the Reproductive Performance of Adult A.I. Boars. (Under the direction of Dr. William L. Flowers). The objective of this study was to examine the effect of birth weight and socialization prior to puberty on reproductive performance of A.I. boars. Twenty boars were randomly allocated to a factorial arrangement of treatments including birth weight (BW: High or Low) and socialization to humans (Socialized or Unsocialized). Boars were trained for semen collection at 150 days of age and then collected once weekly for 27 consecutive weeks. Socialization improved the training success (p < 0.05) and reduced the mounting time (p = 0.007) of Low birth weight boars, but had no effect on these same parameters in High birth weight boars (p > 0.21). Both birth weight (p < 0.001) and socialization (p < 0.001) had a positive effect on total sperm per ejaculate. High birth weight boars that were socialized averaged 77.0 + 2.8 billion compared to 54.1 + 1.9 billion for their low birth weight, unsocialized counterparts. Semen quality parameters including motility, mobility (CASA analyses) and morphology were not affected by either birth weight (p > 0.15) or socialization (p > 0.21). Results from this study indicate that sperm production in adult boars has a positive relationship with birth weight and can be increased further by socialization to humans during their prepubertal development without any detrimental effects on semen quality. In contrast, socialization appeared to enhance libido only in low birth weight boars. Effect of Birth Weight and Human Socialization on the Reproductive Performance of Adult A.I. Boars by Nikhol Elizabeth Dysart A thesis submitted to the Graduate Faculty of North Carolina State University in partial fulfillment of the requirements for the degree of Master of Science Animal Science Raleigh, North Carolina 2014 APPROVED BY: _______________________________ ______________________________ Dr. William L. Flowers Dr. Scott Whisnant Committee Chair ________________________________ Dr. Mark Knauer BIOGRAPHY Nikhol Dysart was born on October 22, 1990 in Anchorage, Alaska to Joe and Karen Garbacik. She has a twin sister, Stefani and a younger sister, Brianna. She graduated from Jack Britt High School in Fayetteville, North Carolina in 2008. After graduating from high school, Nikhol attended North Carolina State University where she received her Bachelor of Science in Animal Science and a minor in Wildlife Management in May 2012. In August 2012, she began to pursue her Master of Science in Animal Science under the direction of Dr. William L. Flowers at North Carolina State University. ii ACKNOWLEDGEMENTS I would like to thank Dr. William Flowers for all of his help during my undergraduate and graduate years at North Carolina State University. His knowledge and experience have helped me so much and I am truly thankful for all he has done. His encouragement in my graduate program has shown me what I am able to accomplish if I only attempt it and I will be forever grateful to him for all of his help. Dr. Flowers is an amazing mentor and has helped me learn to love the swine species. I would also like to thank Dr. Scott Whisnant for all he has taught me about reproduction during my graduate work, as well as for serving on my committee. I would like to thank Dr. Mark Knauer for his time serving on my committee. I would like to extend a special thank you to my fellow graduate student, Charlotte Meli. She was there for every step of the research process for my project. She got up early and stayed late; she loves pigs as much as I do and she was a great help in completing the research for my project. My last thanks go out to my family and husband. My family has been there for me in every aspect of my life, including my educational career. They have supported me and encouraged me in all things. My husband has been with me during the two years of my graduate work; they were probably the most grueling years of school in my career and I am grateful for his support, encouragement, and patience. iii TABLE OF CONTENTS LIST OF TABLES .................................................................................................. vii LIST OF FIGURES ................................................................................................. xii EFFECT OF BIRTH WEIGHT AND HUMAN SOCIALIZATION ON THE REPRODUCTIVE PERFORMANCE OF ADULT A.I. BOARS .............................. 1 LITERATURE REVIEW .......................................................................................... 2 Introduction ..................................................................................................... 2 Puberty in the Boar .......................................................................................... 2 Pubertal Development .............................................................................. 3 Sexual Behavior ....................................................................................... 4 Spermatogenesis Overview ....................................................................... 6 Hormones of Spermatogenesis ................................................................. 8 Semen Quality and Quantity ..................................................................... 9 Summary ................................................................................................ 11 Factors affecting Sperm Production ............................................................... 12 Age ........................................................................................................ 12 Temperature and Photoperiod................................................................. 12 Nutrition and Housing............................................................................. 15 Socialization with Humans ...................................................................... 17 Birth Weight and Litter Size ..................................................................... 18 Summary ................................................................................................... 20 WORKS CITED...................................................................................................... 21 INTRODUCTION ................................................................................................... 24 MATERIALS AND METHODS ............................................................................. 26 iv Animals ........................................................................................................ 26 Farrowing Management and Birth Weight Allocations .................................. 26 Nursery Management and Socialization Allocations ..................................... 27 Finishing Management and Hemsworth Testing ............................................ 29 Management of Adult Boars, Training, and Weekly Collections ................... 30 Semen Quality Analyses ............................................................................... 33 Motility and Mobility ............................................................................. 33 Morphology ........................................................................................... 34 Effect of Different Collection Technicians on Ejaculate Characteristics ........ 35 Semen Quality Estimates of Extended, Stored Insemination Doses ............... 36 Statistical Analyses ....................................................................................... 37 RESULTS .............................................................................................................. 40 Body Weight and Testicular Growth ............................................................. 40 Hemsworth Tests .......................................................................................... 41 Collection Training ....................................................................................... 41 Reaction, Mounting, and Collection Times ................................................... 42 Semen Characteristics ................................................................................... 42 Motility and Mobility of Sperm Cells (CASA Analyses) ............................... 43 Morphology of Sperm Cells .......................................................................... 44 Effect of Different Collection Technicians on Collection Success and Ejaculate Characteristics ........................................................................ 44 Semen Quality Estimates of Extended, Stored Insemination Doses ............... 45 DISCUSSION ......................................................................................................... 46 OVERALL CONCLUSIONS .................................................................................. 54 v WORKS CITED...................................................................................................... 56 TABLES ................................................................................................................. 58 FIGURES ............................................................................................................. 127 vi LIST OF TABLES Table 1. Averages of Socialization on the Treatment groups, Total score for group divided by number of pigs ...................................................................................... 29 Table 2. Changes in Body Weight in High and Low Birth Weight Boars during Lactation .....................................................................................................
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