Johne's Disease Prevention and Control on Organic Dairy Farms in Ontario, Canada
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Johne’s Disease Prevention and Control on Organic Dairy Farms in Ontario, Canada by Laura Pieper A Thesis presented to The University of Guelph In partial fulfilment of requirements for the degree of Doctor of Philosophy in Population Medicine Guelph, Ontario, Canada © Laura Pieper, July, 2014 ABSTRACT JOHNE’S DISEASE PREVENTION AND CONTROL ON ORGANIC DAIRY FARMS IN ONTARIO, CANADA Laura Pieper Advisor: University of Guelph, 2014 Professor David F. Kelton This thesis investigates Johne’s disease (JD) risk factors and control strategies on organic and conventional dairy farms in Ontario, Canada. The JD Risk Assessment and Management Plan (RAMP) was evaluated and used for the comparison of JD control between both farming types. Attitudes about JD control among organic producers and veterinarians were further investigated. RAMP data and JD milk or serum ELISA results from herds voluntarily participating in the Ontario Johne’s Education and Management Assistance Program (OJEMAP) were used for the first three research chapters. Individual interviews and focus groups with organic producers and veterinarians were used in the last two research chapters to understand attitudes about JD prevention and control, as well as about organic farming and the veterinarian-producer relationship. The veterinarian conducting the RAMP greatly influenced the RAMP scores and the recommendations that were given to the producers. However, the RAMP was considered useful in determining the between-herd and within-herd JD transmission risk and in identifying recommendations for JD control for the producers. Organic and conventional farms had a similar herd-level ELISA test-positive prevalence, but affected organic herds had a higher within-herd prevalence than affected conventional herds. Compared to conventional farms, organic dairy farms were found to have higher risk for JD transmission in the calving and calf management areas, but lower risk in the biosecurity area. Contrarily, organic producers received fewer recommendations in the calving and calf management areas. There was hesitation among organic producers to change management practices for JD control and among veterinarians to recommend certain management changes because of organic practices. Organic producers tended to focus on test-and-cull strategies, whereas veterinarians focused on management improvement to control the spread of the disease. While the veterinarian-organic farmer relationships were mostly good, most veterinarians were lacking knowledge about organic farming and did not appear to be the main advisor on many operations. Therefore, education efforts for organic dairy producers regarding approaches for JD control should be increased. Continuing education for veterinarians regarding organic dairy production and regulations might help in improving the veterinary-client relationship and, consequently, in delivery of animal health programs on organic dairy farms. iv Meiner Familie v ACKNOWLEDGEMENTS I would like to thank all the people who helped me accomplish this research. Writing this section has been the most difficult part of the entire thesis. It seems impossible to put into words what each one of you means to me and how you helped me during the process. First and foremost, I would like to thank my supervisor Dr. Dave Kelton for the continuous support in all matters of this research and graduate experience. I am grateful for the trust and freedom that I received from you. During my time in Guelph, I had the opportunity to learn, explore, travel and get to know the scientific community. My experiences were beyond any expectations. I also want to thank my PhD committee, including Drs. Ann Godkin, Ulrike Sorge (Riki), Trevor DeVries, and Kerry Lissemore for their input, advice and support throughout this research. Thank you to all organic dairy producers and veterinarians who participated in the interviews and focus groups. You spent your precious time honestly answering my questions and I hope the results of this research will ultimately help you and others in the industry in controlling and preventing Johne’s disease. Thank you also to Jenny Butcher and Shelly Juurlink from Organic Meadow for their valuable input throughout this project. This project could not have been completed without the financial support through the Ontario Ministry of Food (OMAF) – University of Guelph Research Partnership. The project was additionally supported by an NSERC travel scholarship. Supplementary personal financial support was kindly provided through an Ontario Graduate Scholarship, University International Graduate Scholarships and private donors. I would like to thank all donors for their generosity. vi Thank you, Prof. Staufenbiel, for your suggestion and encouragement to come to Guelph to pursue a PhD in Epidemiology. It turned out as a great experience. Many thanks go to Laura Falzon, Andreia Arruda, Terri Ollivett, Bimal Chhetri, and Khaled Gohary for being such wonderful friends. Thank you also to my other friends and colleagues at Population Medicine, including Jessica and Troy Gordon, Raphael Neves, Cynthia Miltenburg, Christine Murray, Shannon Meadows. I enjoyed the time I was able to spend with you and will work hard to keep in touch. The long discussions about life, culture, and pretty much anything else gave me the opportunity to learn and appreciate different views on the world around me. I believe I grew as a person because of each and every one of you. Thank you to Jill and Jairo Melo and the Mini-Melos for providing a place to live and a home away from home. I will never forget the late-night pool parties and evenings we celebrated together. My special thanks go to Antonio who put up with me for the last 4 years. Thank you for being there to inspire me, to celebrate with me and to lift my spirit when I was down. All of this would have not been possible without the support and encouragement from my parents, Bernd and Marlies, my siblings, Robert and Jule, and my grandparents, Hanni, Ulli and Betty. Thank you for being there for me at all times. vii STATEMENT OF WORK DONE The Ontario Johne’s Education and Management Assistance Program (OJEMAP) was a program conducted independently from this thesis. Nicole Perkins entered most of the RAMP data into a database and Jamie Imada coded the verbal RAMP recommendations into numerical codes. Ann Godkin conducted and coordinated most of the education efforts for producers and veterinarians. Milk and serum samples were analysed for JD ELISA test-positivity by CanWest Dairy Herd Improvement (DHI) and Animal Health Laboratory (University of Guelph, Canada), respectively. Program documents provided in Appendix I.I and I.II were produced by the OJEMAP working group; however, they were included in this thesis to ensure that the context of this work is understandable, even if the documents may be changed or unavailable in the future. The initial proposal for this study was prepared by David Kelton, Ulrike Sorge, Ann Godkin, Gaston Raggio, and Shelly Juurlink. The human ethics approval was prepared by Laura Pieper with the help of David Kelton, Ann Godkin, Trevor DeVries, and Kerry Lissemore. Data management and all statistical analysis were conducted by Laura Pieper. Karen Hand gathered further herd data from CanWest DHI and Dairy farmers of Ontario (DFO). Geographic display of herd participation in CHAPTER 2 was also prepared by Karen Hand. Laura Pieper contacted potential participants for CHAPTERS 5 and 6, conducted all individual interviews and transcribed audio-recordings from interviews and focus groups. The focus groups were conducted by Laura Pieper and Daniel Shock. Qualitative analysis in CHAPTERS 5 and 6 were conducted by Laura Pieper with help from Andria Jones-Bitton. All chapters were written entirely by Laura Pieper and reviewed by all committee members including David Kelton, Ann Godkin, Ulrike Sorge, Trevor DeVries, and Kerry Lissemore. viii TABLE OF CONTENTS CHAPTER 1 MANAGEMENT PRACTICES AND THEIR POTENTIAL INFLUENCE ON JOHNE’S DISEASE TRANSMISSION ON CANADIAN ORGANIC DAIRY FARMS – A CONCEPTUAL ANALYSIS .......................................................................................................... 1 1.1 Abstract ............................................................................................................................ 1 1.2 Introduction ...................................................................................................................... 2 1.3 Canadian organic dairy farming ....................................................................................... 3 1.3.1 Canadian Organic Standards ...................................................................................... 3 1.3.2 Organic dairy industry ................................................................................................ 5 1.3.3 Scientific investigations focused on organic dairy production .................................. 6 1.4 Johne’s disease ................................................................................................................. 9 1.4.1 Etiology and epidemiology ........................................................................................ 9 1.4.2 Diagnostic tests ........................................................................................................ 11 1.4.3 Johne’s disease prevalence and control in Canada ................................................... 14 1.5 Johne’s disease prevalence on organic dairy farms.......................................................