Investigation of Alternatives to Ionophore/Antibiotic Management Strategies in Finishing Cattle and the Inherent Effect on Beef Quality and Shelf Life By Lydia M. Wang A Thesis Presented to The University of Guelph In partial fulfillment of requirements for the degree of Master of Science In Food Science Guelph, Ontario, Canada © Lydia M. Wang, September, 2019 ABSTRACT INVESTIGATION OF ALTERNATIVES TO IONOPHORE/ANTIBIOTIC MANAGEMENT STRATEGIES IN FINISHING CATTLE AND THE INHERENT EFFECT ON BEEF QUALITY AND SHELF LIFE Lydia M. Wang Advisor: University of Guelph, 2019 Dr. Benjamin Bohrer With growing antimicrobial resistance concerns and new regulations limiting the use of antibiotics in livestock production, research for plant-based alternatives to antibiotics with antimicrobial effects is needed. This study investigated the effects of replacing monensin and tylosin with essential oils and(or) benzoic acid in finishing cattle diets. Sixty-eight crossbred steers were blocked by 3 initial weight categories and within each block, 1 of 5 finishing dietary treatments were randomly assigned: control (CON); monensin/tylosin (M/T); essential oil (EO); benzoic acid (BA); and a combination of EO and BA (COMBO). Monensin/tylosin supplemented steers had greater feed efficiency compared with steers fed CON, EO, and COMBO diets. However, EO and(or) BA supplemented beef finishing diets did not negatively affect most other major growth performance, carcass characteristics, meat quality, sensory traits, colour and oxidative stability of steaks and ground beef when compared with cattle fed no additives or conventionally fed cattle supplemented with M/T. iii ACKNOWLEDGEMENTS Like many things in life, this project has been a total team effort and I would not have been able to complete it without the support of many individuals and organizations. Firstly, I want to express my sincere gratitude to my advisor Dr. Benjamin Bohrer. I am very thankful that he took me in as his Masters student and gave me a plethora of learning opportunities along the way. I will be forever grateful for all his mentorship, teachings, encouragement and critiques, all of which have helped me grow tremendously. Many thanks to my advisory committee members, Dr. Ira Mandell, Dr. Lisa Duizer, and Dr. Don Mercer, for taking valuable time out of their schedules to share their knowledge with me and providing advice and feedback on my project along the way. I would really like to thank Cheryl Campbell, for training me on many meat science protocols, allowing me to work in her lab, and sharing her technical expertise. Thank you to Dr. Michelle Edwards, for her statistical guidance and teachings. Additionally, I would like to thank and acknowledge the help and cooperation of the University of Guelph Meat Laboratory staff, Brian McDougall, Judy Kendall and Sam Leo, as well as the staff at the Elora Beef Research Station, for their excellent management of all the cattle in this trial. Further thanks go to the Food Science Department administrative staff, Tricia Townsend and Leona Varga for all their help. I would like to acknowledge the OMAFRA - U of G Research Program, Beef Farmers of Ontario, DSM Nutritional Products, and Weston Seeding Food Innovation Program for their financial assistance in this project. Thank you to the HQP Scholarship Program for giving me this opportunity to further my education without being in deep debt. To all my lab mates – Shiqi (Kay) Huang, Sebastian Chalupa-Krebzdak, Sandra Milena Vasquez Mejia, Ziyu (Amy) Zhou, Robson Sfaciotti Barducci, and Claudio Gabiatti – thank you guys so much for your assistance with this project, your friendship and support. Special thanks also to all of the undergraduate students who have helped me complete the lab work. It has been a great pleasure working with you all. I am extremely grateful and lucky to have such wonderful friends in my life who constantly uplifts and encourages me. Huge thanks to Sydney Gosselin for all the interesting conversations, meals shared, and enduring all my rants for the past two years. Without a doubt, my biggest emotional support came from my family. To my mom and dad – my favourite people on Earth – thank you SO, SO much for your unending love, care, support, encouragement, advice, sacrifices, prayers, and always being just a phone call away. Thank you for teaching me life’s lessons and pushing me to be the best version of myself. You two will always be my role-models and heroes. Moreover, many thanks to my grandparents and extended family for their constant love and being my cheerleaders in life. Last and not least, all would not be possible without my Lord and Saviour, Jesus Christ. He has and continues to bless me in so many ways. Philippians 4:13. iv Table of Contents ABSTRACT .................................................................................................................................... ii ACKNOWLEDGEMENTS ........................................................................................................... iii TABLE OF CONTENTS ............................................................................................................... iv LIST OF TABLES ........................................................................................................................ vii LIST OF FIGURES ..................................................................................................................... viii CHAPTER 1 GENERAL INTRODUCTION .................................................................................1 1.1 Objectives ...............................................................................................................................3 1.2 Hypotheses .............................................................................................................................3 1.3 Literature Cited ......................................................................................................................4 CHAPTER 2 LITERATURE REVIEW ..........................................................................................7 2.1 Ionophores ..............................................................................................................................7 2.2 Monensin ................................................................................................................................9 2.2.1 Effects of Monensin On Rumen Fermentation .............................................................11 2.2.2 Effects of Ionophores (Monensin) On Rumen Microorganisms ..................................12 2.2.3 Effects of Monensin On Cattle Performance ................................................................14 2.2.4 Ionophore (Monensin) Resistance ................................................................................15 2.2.5 Monensin Inclusion Rate ..............................................................................................17 2.3 Tylosin Phosphate ................................................................................................................17 2.3.1 Tylosin and Liver Abscesses ........................................................................................19 2.3.2 Tylosin Resistance ........................................................................................................22 2.3.3 Inclusion Rate ...............................................................................................................24 2.4 Essential Oils ........................................................................................................................25 2.4.1 Thymol ..........................................................................................................................27 2.4.2 Eugenol .........................................................................................................................29 2.4.3 Limonene ......................................................................................................................30 2.4.4 Vanillin .........................................................................................................................31 2.5 Organic Acids .......................................................................................................................32 2.5.1 Benzoic Acid .................................................................................................................33 2.6 Conclusion ............................................................................................................................35 2.7 Literature Cited ....................................................................................................................36 v CHAPTER 3 THE EFFECTS OF FEEDING ESSENTIAL OILS AND(OR) BENZOIC ACID FOR REPLACING ANTIBIOTICS ON FINISHING CATTLE GROWTH PERFORMANCE, BEEF CARCASS CHARACTERISTICS, AND BEEF SENSORY ATTRIBUTES ...................52 ABSTRACT ...............................................................................................................................53 1. Introduction ............................................................................................................................55 2. Materials and Methods ...........................................................................................................56 2.1 Cattle and Facilities .........................................................................................................56 2.2 Treatments and Experimental Design ..............................................................................58