Veterinarians treating diseased animals appreciate that nutritional management is an important part of therapy. Many types of premium basic, life-stage, and therapeutic commercial diets are available to address these needs. For example, increasing carbohydrate and reducing protein content, while maintaining high quality protein, may be beneficial, and is also believed to have a positive effect on behavior. Diet and behavior appear to be linked because certain highly nutritious foods may aggravate the condition of dogs with behavioral problems (dominant aggression, hyperactivity, and fear). For allergic animals, elimination diets with restricted or novel antigen source ingredients are given for 6-12 weeks to evaluate their benefit to the patient.

Homemade diets can also be used, either as a sole food source or added to basic cereal diets, provided that the formula is properly balanced. All other food supplements, including treats, are withdrawn. Example ingredients that have been used successfully, include whitefish, rabbit, venison, duck, ostrich, emu, buffalo, and turkey mixed with potato, sweet potato and other vegetables (except onions and cruciferous vegetables). Grains are often avoided, at least initially, although novel grains like quinoa, sorghum, barley or flax usually have been well tolerated.

Commercial or home-made raw food diets have been gaining in popularity as well. One prototype diet [BARF (bones and raw food)] of Dr. Ian Billinghurst recommends feeding a dog 60% raw meaty bones (chicken backs,wings and necks), with the rest of the diet composed of ground vegetables mixed with ground meat, and supplements such as kelp, vitamin E and vitamin C. Nutritional analyses on some commercially available raw diets suggest that the raw meaty bones commonly used provide 40-70% protein, and the meat/vegetable mixtures range from 20-50% protein. The question has arisen about the potential for such high protein diets to affect renal function when fed continuously, as high protein diets are reported to induce renal hypertrophy, and increase renal blood flow and glomerular filtration rate. While this concern may not pertain to healthy dogs, it could play a role in dogs with previously compromised renal function. At present, there are no data to support or refute this issue.

Maintaining the appropriate ratio of trace minerals, vitamins, fatty acids and other nutritive elements is especially important for patients with acute and chronic diseases, as their metabolic demands have increased to sustain cell turnover and tissue repair. Typical supplements include: vitamin-mineral mix, antioxidants (vitamins A, C, D, and E and selenium), digestive enzymes, brewer's yeast, kelp, honey, coat additives, apple cider vinegar, hydrochloric acid (used sparingly), yogurt, liver, eggs, garlic, and plenty of fresh potable water.

Vitamin A and E have been shown to enhance immune function in small animals, as the former can beneficially influence T-helper responses, and the latter is known to improve both cellular and humoral immunity. Dietary carotenoids, especially lutein and beta-carotene, have been reported to modulate both cell-mediated and humoral immunity in dogs but not in cats.

Antech Diagnostics recently determined the basic clinical laboratory parameters of 227 healthy adult dogs of varying ages and breed types being fed raw food diets for at least 9 months. From this group, 87 dogs were fed the classical BARF diet, 46 dogs were fed VolhardŐs NDF diet, and the remaining 94 dogs were fed other types of custom or commercial raw diets.

There were 69 dog breeds represented, including 233 purebreds, 16 crossbreds, 1 mixed breed and 6 of unknown breed type. Dogs from all breed groups were represented. Most of the dogs were neutered males (73) or spayed females (85); and the remainder was divided equally between intact males and females. The mean age of the group was 5.67 ± 3.52 years (mean ± SD); and the mean length of time fed a raw food diet was 2.84 ± 2.54 years. The data from this group of dogs were compared to the same laboratory parameters measured at Antech Diagnostics from 75 healthy adult dogs fed a commercial cereal-based kibbled diet. Statistical comparisons of results for the raw and cereal-based diets found them to be essentially the same with the following notable exceptions:

• Higher packed cell volume (hematocrit) in all raw diet fed groups (range of 51.0 ± 6.6–53.5 ± 5.6 %) versus cereal-based kibble (47.6 ± 6.1%).
• Higher blood urea nitrogen (BUN) in all raw diet fed groups (range of 18.8 ± 6.9–22.0 ± 8.7 mg/dL) versus cereal-based kibble (15.5 ± 4.7 mg/dL).
• Higher serum creatinine in the Volhard raw diet group only (1.20 ± 0.34 mg/dL) versus cereal-based kibble (1.07 ± 0.28 mg/dL).

While a more detailed analysis has yet to be completed, these results indicate that dogs fed raw meats (natural carnivores) have higher red blood cell and blood urea nitrogen levels than dogs fed cereal-based food (obligate omnivores). Thus, the normal reference values for dogs fed raw food diets should probably be revised.