Robert A. Godke, for their help and support with my thesis research. I am extremely indebted to Mr. Franklin "Randy" Wright for his management of the horses during these experiments. A sincere thanks goes to my colleagues who have greatly helped me throughout my graduate career with great support and understanding. First, thank you William A. Storer for your many hours worked at the farm and much needed, directional advice with these intensive projects. A huge thanks goes to Pamela B. Mitcham for her many hard hours and helpful advice. A very special thanks goes to to John Vidrine for all his help and dedication. Jodi Crowley and Maxon McKean, thank you for your support, and Laura R. Gentry, thank you for the much appreciated help with data analysis and radioimmunoassay techniques. Also, gratitude is extended to all the student workers whose hard work, both in the lab and at the farm, was invaluable. My most sincere appreciation is extended to my grandmother, Louise Wyrick, for her support, love, and encouragement throughout my academic career. I also thank my family and friends for their advice, support, and love. iii TABLE OF CONTENTS

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