Helen Sheard MVS.Pdf (972
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Demographics and Health of New Zealand Working Farm Dogs: A survey of dogs on sheep and beef farms in New Zealand in 2009. Thesis submitted by Helen Sheard in partial fulfilment of the requirements for the degree of Master of Veterinary Medicine Institute of Veterinary, Animal and Biomedical Sciences Massey University, Palmerston North, New Zealand June 2014 2 I hereby certify that the thesis has not been submitted for a higher degree at any University or Institution and work embodied in this thesis is my work unless noted otherwise in the acknowledgements. Helen Sheard 3 4 Dedicated to Belle, Jack and Hoon, Huntaways supreme; and to Shears and Bubbles – you know who you are. 5 6 Abstract The aim of this study was to investigate the demographics, disease prevalence and risk factors for death in a population of working farm dogs in the lower North Island of New Zealand. To this end, a cross-sectional study of working farm dogs was undertaken in 2009. Owners were randomly selected from farms in the lower North Island of New Zealand using AgribaseTM, a farm database maintained by AsureQuality. All owners were interviewed by one researcher. Completed surveys were received from 118 farms, providing data for 1,115 dogs. Any dog that had been present on the farm in the 12 months preceding the survey was eligible for inclusion. By using this criteria data was able to be collected from dogs that were dead or had been sold, as well as those that were alive. Data from dogs less than 6 months old were excluded on the premise that they did not contribute to the working population. 79% (n=885) of enrolled dogs were alive and on the farm at the time of the survey, 15% (n=167) were dead and 6% (n=63) had been sold or given away. The average age of working dogs in the study population was 5.2 years (median 5 years, range 7 months to 18 years). Of the dogs enrolled in the survey, 653 (58.6%) were males and 462 (41.4%) females. For those dogs whose neuter status was known, 3.6 % of males (n= 23/647) and 10.4% of females (n=48/461) were de-sexed. The majority of breeds were the NZ Huntaway (n=531/1115, 47.6%) and the NZ Heading dog (n=402/1115, 36%). The majority (73.4%) of dogs were fed once daily, in the evening, primarily on a diet of home-kill sheep meat (58.3%, n=427). During the study period, 1,267 health events were recorded from 1,115 dogs. Of the recorded health events, 69.9% (n=886) were described as non-trauma events, 28.3% (n=358) were described as trauma events, and 1.8% (n=23) were described as congenital events. The health event most commonly reported by the owner (n =210, prevalence 18%), was the dog being underweight. Arthritis was the next most common health event reported, with a prevalence of 10.22% (n=114 cases). Injury or excessive wear to the pads was the most commonly reported traumatic event (5.56%, n=62), however the musculoskeletal system and integumentary systems were equally involved in traumatic events. Forty-eight dogs suffered limb fractures (4.3%) and 30 were injured by stock (2.69%). 7 Variables that increased the risk of a dog being dead were suffering more than one non- trauma event (p<0.0001), and residing on farms that had larger numbers of dogs present. When compared with dogs ≤ 2 years of age, the risk of a dog being dead decreased in ages between two and seven years. Dogs that were considered to be underweight, or those that had suffered an axial/limb fracture, were less likely to be dead than those that had not. Analysis of the data in this survey found no significant risk associated with career stage, breed, sex, neuter status, working on a farm with steep terrain, arthritis with or without lameness, or musculoskeletal injury. Future research could focus on the importance of nutrition in the prevention of disease and injury; for example, constipation and musculoskeletal injury. The ideal body condition score, optimum diet composition and frequency also require investigation. Further to this survey, risk factors associated with a dog being lost from the working population due to death or euthanasia need to be identified so preventative measures can be developed. 8 Acknowledgements Sincere thanks to Naomi Cogger, my primary supervisor, for her guidance and patience with data analysis; and to Kate Hill and Boyd Jones for their proofreading help, support and encouragement for a complete novice. Also to Amy Jerram, who conducted the face-to-face interviews with farmers and collected such a wealth of data that I was able to analyse a proportion of it for this thesis. I would also like to acknowledge the generous financial contribution of both the New Zealand Companion Animal Health Foundation and the Massey University Centre for Service and Working Dog Health. And as always, to family and friends who are there keeping things real. 9 10 Table of contents Abstract ..........................................................................................................................................7 Acknowledgements ........................................................................................................................9 Table of contents ........................................................................................................................ 11 List of Figures .............................................................................................................................. 15 List of Tables ............................................................................................................................... 17 List of Abbreviations ................................................................................................................... 19 1 Introduction ....................................................................................................................... 21 2 Literature review ................................................................................................................ 25 2.1 Introduction ............................................................................................................... 27 2.2 Demographics ............................................................................................................ 28 2.3 Causes of loss ............................................................................................................. 29 2.4 Nutrition .................................................................................................................... 31 2.4.1 Macronutrients ..................................................................................................... 31 2.4.2 Micronutrients ...................................................................................................... 32 2.5 Adverse health events ............................................................................................... 33 2.6 Toxicity/Poisoning in working farm dogs .................................................................. 34 2.6.1 MCPA toxicity ........................................................................................................ 35 2.6.2 Macrocyclic lactone toxicity .................................................................................. 35 2.7 Non-traumatic diseases ............................................................................................. 36 2.7.1 Disease of the gastrointestinal system ................................................................. 36 2.7.2 Disease of the Integumentary system .................................................................. 40 2.7.3 Disease of the Respiratory system ........................................................................ 41 2.7.4 Disease of the Reproductive system ..................................................................... 43 2.7.5 Ocular disease ....................................................................................................... 43 2.7.6 Neosporosis ........................................................................................................... 44 11 2.7.7 Leptospirosis ......................................................................................................... 45 2.7.8 Campylobacteriosis ............................................................................................... 46 2.7.9 Salmonellosis ......................................................................................................... 46 2.7.10 Tyzzer’s disease ................................................................................................. 46 2.8 Breed predispositions for disease ............................................................................. 47 2.8.1 Hip dysplasia .......................................................................................................... 50 2.8.2 Heart disease ......................................................................................................... 51 2.8.3 ABCB1 gene mutation ........................................................................................... 51 2.8.4 Other genetic disease ............................................................................................ 52 2.9 Disease of the Musculoskeletal system ..................................................................... 52 2.9.1 Lumbosacral stenosis ............................................................................................ 52 2.9.2 Degenerative joint disease .................................................................................... 53 2.10