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Nutritional Balance |
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 As raw diets can range from meticulously prepared and tested to diets composed of a variety of meats and butchers' scraps, the nutritional balance of a raw diet can vary greatly depending on the recipe. However, supporters of raw feeding believe that not every meal needs to be "complete and balanced", and that nutritional balance can be achieved over time by feeding a wide variety of meats, fats, bones and organs from several sources, such as chicken, turkey, lamb, cattle, pigs, fish, rabbits, etc, and even wild game. The general belief among the supporters of raw diets is that pets have no more complex nutritional requirements than humans, and that a variety of ingredients over time will provide the pets with a sufficiently balanced diet.
Many who oppose raw diets believe that the Association of American Feed Control Officials (AAFCO) standards that many commercial pet food comply with gives an assurance of quality that homemade food cannot give. One study that analyzed the nutritional content of three homemade diets (BARF, Ultimate and Volhard) and two commercial raw food diets(Steve's Real Food and Sojourner Farms) and compared it to the AAFCO standards, showed that nutritional imbalances occurred in multiple areas. Three of the diets had abnormal calcium-to-phosphorus ratios which can lead to hyperparathyroidism and fibrous osteodystrophy in puppies.
A 12-month study undertaken for the Winn Feline Foundation by researchers from the UC Davis School of Veterinary Medicine sought to compare the effects of a whole ground rabbit diet with a high quality commercial diet on 22 kittens and adolescent cats. The ground whole rabbit diet(including fur and organs) was frozen in small batches and thawed prior to feeding. The researchers noted the superior palatability of the raw rabbit diet. Significant stool quality improvements were seen in the raw rabbit diet group after one week. After one month, the raw diet group had firm, non-odorous and well formed stools while the commercial diet group had soft formed to liquid stools. The raw diet group also appear to have better coat quality. There were no differences between the groups in terms of growth rate, degree of inflammation in the intestinal tract and the numbers of bacteria in the upper small intestine, although a slightly higher number of cats in the raw diet group were shedding pathogenic organisms (Giardia and Cryptosporidia) in their stools. Ten months into the study, one cat in the raw diet group died suddenly from dilated cardiomyopathy due to a severe taurine deficiency. 70% of the group had heart muscle change compatible with taurine deficiency. The researcher ascertained that the raw rabbit diet contained the minimal requirement of taurine but speculated that bacteria in the rabbit carcasses might have broken down some of the taurine. The processing and grinding of the rabbit might have also caused some of the taurine to be destroyed due to the low level of vitamin E in the diet. The authors conclude that "a natural diet may not always be as healthy as imagined, and that even measuring nutrient values may not predict how a diet will perform after being fed for many months."
When feeding a raw diet, even some proponents of raw diets recommend frequent analysis by a veterinarian or animal nutritionist to verify that proper nutrients are being ingested. Other proponents sometimes dismiss the importance of AAFCO standards, claiming that AAFCO certification is not indicative of the quality of a diet. An AAFCO panel expert has stated that "although the AAFCO profiles are better than nothing, they provide false securities." Many cite that the oldest dog ever recorded, a 29-year-old Australian cattle dog named Bluey, died in 1939, several years before commercial pet food was invented, and that, of the two oldest dogs in recent years, one was fed primarily on kangaroo and emu meat.
Bones and dental health
Some proponents of raw diet claim noticeable benefit to the dental hygiene of pets who eat raw bones, while others believe that ground bone should be used instead, to prevent the possibility for intestinal puncturing and dental fractures. The abrasion between bone and teeth when chewing is believed to scrape off dental plaque. Cartilage, ligaments, and tendons are thought to act as a natural dental floss. The chewing and tearing action is also believed to strengthen the jaw, neck and shoulder muscles, keep the digestive juice flowing and boost the neurological and immune system. Proponents of ground bones believe that the chewing of muscle meat may also assist in keeping teeth clean.
The use of whole bone creates a risk of dental fractures, intestinal obstruction, gastroenteritis, and intestinal perforations. Wolf care managers questioned on the topic of feeding bones identified the presence of animal hide with hair as offering some protection from intestinal perforation in the wild. An analysis of the skulls of African wild dogs showed that the natural diet of wild carnivores does not prevent them from suffering the same oral disease as their domestic counterpart, although other studies have had results that claim otherwise. Raw diet proponents note that the same risks of obstruction, puncturing, and dental fractures are present in dog chews, with little evidence indicating that this is a serious problem particular to raw diets with bones. Some veterinarians state that chewing raw bone is an inadequate substitute for regular dental cleaning and tooth brushing.
Bacteria, viruses and parasites
While the intense heat used in manufacturing pet food destroys any potential bacteria, raw meats may contain bacteria that are unsafe for both dogs and cats. The US Government reported that in 2006, 16.3% of all chickens were contaminated with salmonella. A study on 25 commercial raw diets for dogs and cats detected salmonella in 20% and Escherichia coli in 64% of the diets. However, the E. coli strain that can cause severe illness H157:O7 was not tested for. An example of the severity of E. coli H157:O7 infections can be seen in affected greyhound racing dogs fed raw meat as part of their diet. Known in greyhounds as "Alabama rot", the disease causes severe vasculitis, cutaneous necrosis, renal failure and death. It should be noted that racing greyhounds are typically fed raw meat classified as "not for human consumption", which may contain higher than normal levels of bacteria.
Raw feeders consider the risk overblown and claim that the stomach enzymes and short intestinal tracts of dogs and cats allow them to handle harmful bacteria. For example, an outbreak of Salmonella caused by tainted commercial dry dog food led to 62 cases of human infection but no reports of the disease affecting animals fed the tainted food. On the other hand, there has been a reported case where two cats fed a raw diet developed salmonellosis and died as a result. A veterinarian from the National Animal Poison Control Center suggests that the diarrhea in animals that raw feeders attribute to detoxing could be caused by pathogens such as salmonella, E. coli, clostridium and campylobacter. The purchase of good quality meat from reputable sources and proper food safety practices such as defrosting meat in the refrigerator and not leaving food out for too long can reduce the proliferation of bacteria present in the meat.
Raw meats may also contain harmful parasites. As with bacteria, these parasites are destroyed during the heat processing of manufactured pet foods. Some raw diet recipes call for freezing of the final product, which greatly reduces (but does not necessarily eliminate) the potential for parasites. According to European Union regulations, freezing fish at -20°C (-4°F) for 24 hours kills parasites. The FDA recommends freezing at -35°C (-31°F) for 15 hours, or at -20°C (-4°F) for 7 days. The most common parasites in fish are roundworms from the family Anisakidae and fish tapeworm. While freezing pork at -15°C (5°F) for 20 days will kill any trichinella spiralis worm, trichinosis is rare in countries with well established meat inspection programs, with cases of trichinosis in humans in the United States mostly coming from consumption of raw or undercooked wild game. Trichinella species in wildlife are resistant to freezing. In dogs and cats symptoms of trichinellosis would include mild gastrointestinal upset (vomiting and diarrhea) and in rare cases, muscle pain and muscle stiffness.
A survey of accredited zoos worldwide showed a slightly increased risk of parasites and diseases in animals that are carcass fed as compared to commercial food fed. However, the researchers suggested that that may be caused by increased opportunistic preying and infected live preys may be the source of contamination.
Zoonotic risk
A possible risk of raw feeding is that of human infection caused by direct or indirect exposure to bacterial pathogens in raw meat and animal stools. For example the British Veterinary Association warns that humans "risk exposing themselves to bacteria like salmonella". A small study on the levels of salmonella in the stool of 10 dogs that ate a raw diet found that 80% of the raw diet tested positive for Salmonella spp. and while 30 percent of the stool samples from dogs fed a raw food diet contained salmonella, none of the control dogs (commercial fed) contained salmonella. The authors of the study concluded that dogs on a raw food diet may therefore be a source of environmental contamination, although they caution about the statistical significance of their results due to the small number of dogs studied.
Because of the potential animal and human health risks, veterinarian organizations and public health agencies believe that the risks inherent in raw feeding outweigh the purported benefits. Despite such concerns, there is no known incidence of humans being infected with salmonella by cats and dogs fed a raw diet. Again, proper food safety precautions such as wiping down preparation surfaces and careful disposal of stools can reduce the risk of infection.
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Balance
