Changing the metabolism of dogs (Canis familiaris) and cats (Felis catus) at rest and during exercise by manipulation of dietary macronutrients : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Nutritional Science, at Massey University, Palmerston North, New Zealand.

Worldwide, dogs are used for a vast range of activities, however, in New Zealand the most valuable and common are those that play a key role in the daily management of farms. These dogs are invaluable for farmers and therefore providing them with optimum care and nutrition is of paramount importance. However, despite their importance, there is very little information regarding the nutrition of these „intermediate‟ working dogs and others such as hunt and agility dogs, although a significant amount of research exists focussing on sled dogs and greyhounds; the marathon runners and sprinters of the canine world. Today many farmers in New Zealand feed home kill meat to their dogs, often supplemented with commercial dry biscuits. The major issues associated with these diets are that home kill can be deficient in many micronutrients; while commercial dog biscuits contain high carbohydrate levels and large quantities of both of these feeds need to be consumed for the dog to meet its nutrient requirements. The ideal diet for working dogs should be highly digestible, palatable and energy dense as their stomach capacity is limited and they are often too tired to eat a large amount after exercise. Ultimately the goals of nutrition for working dogs should be to maintain health and immune function, minimise injury and optimise performance by providing a sustained energy source during their long periods of exercise. The aims of this thesis were to evaluate the effects of dietary macronutrients on animal metabolism during exercise and at rest in cats and dogs. This was achieved by determining apparent digestibility, post-prandial glycaemic and insulinaemic responses, large intestinal carbohydrate fermentation, weight maintenance, exercise performance, immunity and fuel utilisation during exercise in working dogs (with exercise or at rest) and/or cats (at rest). Diets with macronutrient profiles giving better glycaemic control and increased satiety may be beneficial for the cat esp