Obesity is recognised as the leading cause of malnutrition in cats and dogs (Legrand-Defretin 1994) and is reported to be one of the most important and frequently seen welfare issues in small animal practice (Yeates and Main 2011). Despite the recognised burden of overweight/obesity on the companion animal population, a review of the published literatureidentified several gaps. This thesis aimed to address three of the those gaps.
Gap A: No published national prevalence estimates for cats, dogs and rabbits in Great Britain were available and no studies had explored whether prevalence varied across Great Britain. Chapter 3 and 4 estimated the national prevalence of overweight/obesity in cats, dogs and rabbits to be 11.5%, 25% and 7.6% respectively. After adjusting for differences in demographics between locations, there was a significantly higher prevalence of canine overweight/obesity in Scotland compared to England and Wales. But no spatial variations were found in the prevalence of feline overweight/obesity within Great Britain.
Gap B: There was a lack of consistency in the risk factors found to be associated with overweight/obesity between previous published studies and no assessment of the impact of various risk factors on the prevalence of canine and feline overweight/obesity was apparent in the literature. Non modifiable risk factors identified for dogs in Chapter 3 included being female, neutered status, and age with peak of risk at 5 to 8 years of age. These effects were independent of location. Chapter 4 identified neutered status, being male and middle age (around 7 years) as feline non modifiable risk factors. Neutered status was the only significant risk factor found for rabbit overweight. Chapter 5 and 7 expanded the canine and feline overweight/obesity risk factor analyses to include modifiable risk factors. Risk factors for canine overweight/obesity (Chapter 5) identified were owner income, owner age, frequency of snacks and treats and hours of exercise the dog received each week. For cats (Chapter7), the significant risk factors were frequency of feeding and neutered status. The calculated population attributable risks (Chapter 3 and 4) showed possible differences in the impact of non modifiable risk factors between cats and dogs. For cats, neutered status was the most important factor whereas in dogs age and neutered status were equally important.
Gap C: Misperception of body shape has been recognised to play an important role in human obesity management. Previous studies had only described owner misperception of pet body shape as a risk factor for obesity/overweight. The objective of Chapter 6 and, in part, Chapter 7 was to explore the concept of owner misperception of canine and feline body shape. Owners of cats and dogs appeared to “normalise” their animal’s body shape i.e owners of overweight animals were more likely to think their pet was an ideal shape rather than overweight and owners of underweight animals were more likely to think they were an ideal shape rather than underweight. Risk factors identified for misperception in dog owners were gender of owner and age of the dog. Only one risk factor was identified for misperception by cat owners; that is whether the cat was long haired or not.
In conclusion, this thesis demonstrates that overweight/obesity in cats, dogs and rabbits is widespread. Despite the limitations of these data, the results show the complexity of risk factors that contribute to overweight/obesity in companion animals and highlight areas for future research
