Raw feeding

Raw feeding is the practice of feeding domestic dogs, cats and other carnivores a diet primarily of uncooked meat, edible bones, and organs.

Supporters of raw feeding believe that the natural diet of raw meat, bones, and organs is nutritionally superior to cooked meat and commercial pet food. They argue that a careful plan of a raw diet gives the animal numerous health benefits, including a healthier coat and cleaner teeth and elimination of bad breath. Critics of raw feeding assert that the risk of nutritional imbalance, intestinal perforations and foodborne illnesses posed by the handling and feeding of raw meat and bones outweigh any benefits. The assertion that raw feeding is inherently better because it is natural has also been criticized.

Few studies have been done to prove or disprove the numerous beneficial claims of a raw diet.

Rationale

Objection to commercial pet food

There are numerous arguments over the health effects of feeding commercial pet foods, and many raw feeding pet owners claim to have noticed a significant increase in overall health after switching to a raw food diet.

Because commercial pet foods are assumed to be the primary or exclusive element of a pet's diet, manufacturers enrich their product by supplementing the food with vitamins and minerals. As the heat used to process commercial pet foods may reduce the level of naturally occurring nutrients,^[1] critics question the actual nutritional value of commercial foods. Critics argue that there may be elements to pet nutrition yet to be discovered or that are not understood well enough to be supplemented. There is skepticism over the efficacy of supplements vs the natural absorption of naturally occurring nutrients. The same rationale is used by some to reject supplemented home cooked pet food. A study involving rats has suggested that the digestibility of the amino acids in cat food is altered during heat processing.^[2]

Commercial pet foods, dry foods in particular, often contain a large amount of grains, which proponents of grain-free food feel are inappropriate for dogs and cats. Because cats are obligate carnivores, it is believed that a switch to a predominantly meat based raw diet would be especially beneficial (as compared to a raw diet for dogs) due to cats' relative inability to digest grains. Studies comparing the source of protein in dry cat food concluded that the digestibility of meat-based protein is superior to corn-based protein.^[3]

Veterinary surgeon and raw feeding proponent Tom Lonsdale states that food from dry or canned commercial kibble sticks to teeth and enables bacteria to proliferate, causing "sore gums, bad breath and bacterial poisons that affect the rest of the body". Lonsdale further states that dogs lack the necessary enzymes to digest grains and plant material and claims that grains cooked at high temperature can cause starch, proteins and fats to become "denatured or toxic in variable degrees." The poorly digested grain is said to support toxin-producing bacteria in the lower bowel which may eventually lead to "poisons pass[ing] through the bowel wall into blood circulation" creating further problems in other organs.^[4]

Another concern about commercial pet food is the often poor quality of meat. Factory-farmed meat may have a variety of health consequences, and pet owners who care about the humane treatment of animals may object to factory farming conditions. Raw food brands typically source their ingredients more carefully, though there are some non-raw commercial brands that focus on using good sources of meat.

Objection to cooked meat in general

Raw food proponent Dr Ian Billinghurst (owner of the registered trademark 'Barf Diet' and the BARF World Distributor Network) argues in his books that the dog has evolved over many million years on a natural raw diet and logically, this is the ideal food source. He claims that processed foods are "not what [the] dog was programmed to eat during its long process of evolution" and says that foods similar to those eaten by the dog's wild ancestors are more biologically appropriate.^[5]

Proponents have also pointed at the practices of some modern zoos which feed their captive carnivores raw meat and bones or whole carcasses.^[5][6] The curator of the Folsom City Zoo Sanctuary has said that "Common sense suggests that there is no more nutritious food we can offer to a carnivore than the entire carcass of their natural prey type." While raw feeding is generally well accepted in European zoos, it is a controversial topic within American zoos.^[7] Concerns are similar to those expressed by opponents of raw feeding and includes dental impactions, airway obstructions, intestinal perforations, food contamination and social aggression. Benefits include better oral health, mental stimulation through processing of carcass (see Behavioral enrichment) and higher activity level. ^[8]

Critics have pointed out the flaws in associating "natural" with better^[9] and Billinghurst himself warns against that stating "There are grave dangers that go along with the natural diet and natural conditions the ancestors or wild cousins of our dogs live with."^[5] Katie Merwick, who runs an animal rescue sanctuary cautions against "making a fetish out of what animals eat in the wild"[paraphrased]^[9]

Pottenger's cat

One study used to back up the claims of raw food being superior to cooked food is Francis M. Pottenger, Jr.'s study of 900 cats over a period of 10 years from 1932 to 1942.^[10] His results showed that cats that were fed 2/3 raw meat, 1/3 raw milk and a small amount of cod liver oil were disease free and healthy while those fed the same food with the meat cooked developed degenerative diseases and reproductive difficulties, with new generations plagued with health problems. The study was done before the importance of taurine in a cat's diet was known and it has been suggested that the group of Pottenger's cats on cooked food simply suffered from taurine deficiency as heating or cooking food causes a reduction in taurine content.^[11] In a study on feline maternal taurine deficiency, the group of taurine-deficient cats exhibited symptoms similar to the Pottenger's cats on a cooked diet.^[12]

In another study, the cats were fed 2/3 milk and 1/3 meat. All groups were fed raw meat with different groups getting raw, pasteurized, evaporated, sweetened-condensed, or raw, metabolized vitamin D milk. The cats on raw milk were the healthiest while the rest exhibited varying degrees of health problems similar to the previous cooked-meat study.^[13] This study has been cited by raw milk proponents as evidence of the benefits of raw milk.

History

Herbalist Juliette de Bairacli Levy is credited with being an early advocate of raw feeding. In her books, she argues, amongst other things, that dogs require a natural diet of raw food.^[14]

Raw diet types

There are various differences in opinion within the raw feeding community. Issues include the question of whether dogs are omnivores or carnivores. Also, whether cats and dogs need plant material in their diet, and if so, the proportion of such material. The safety of whole bones is also a frequent topic of discussion. Recipes that are advocated range from those that include vegetables and grains, to a minimalist approach using only meat, bones, organ meat, and necessary supplements such as the Meat with Bone diet advocated by Michelle T. Bernard.^[15]

Barf

The "BARF" diet, an acronym for Biologically Appropriate Raw Food or Bones And Raw Food was created by Billinghurst. The acronym was coined by Debra Tripp. A typical BARF diet is made up of 60-80% of raw meaty bones (RMB), that is bones with about 50% meat,^[16] (e.g. chicken neck, back and wings) and 20-40% of fruit and vegetables, offal, meat, eggs, or dairy foods.

Prey model

The "prey model" diet attempts to simulate the proportions of an actual prey animal in a pet's diet. Actual whole prey are used whenever possible, including whole rabbits, chickens, game hens and turkeys. Generally, the diet recommends 80% meat (including some 'meaty' organs such as heart), 10% bone and 10% organs (of which half is liver). Proponents of the whole prey model diet believe dogs and cats are both natural carnivores and therefore there is no nutritional or dietary need for anything other than meat, bones, and organs.^[17][18] The supporters of the prey model also focus on feeding meats from a wide variety of animals. Some also add small amounts of vegetable matter to simulate the consumption of stomach contents of prey animals.

Supplements are generally not used in a prey model diet although some followers do add fish oil to the diet to compensate for the reduced amount of omega-3 fatty acid in commercially raised grain-fed livestock.^[19] This problem can be partially mitigated by using grass-fed meat, which has more than double the omega-3 content as grain-fed meat.^[20]

Nutritional balance

The nutritional balance of a raw diet can vary greatly depending on the recipe. Some raw diet proponents prefer to use a variety of ingredients, believing that will provide a more balanced diet than a single primary food.

The Association of American Feed Control Officials (AAFCO) provides standards that guides many commercial pet food companies, a level of supervision that does not occur with homemade food. One study 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, showing nutritional imbalances in the homemade diets.^[21] Three of the diets had abnormal calcium-to-phosphorus ratios which can lead to hyperparathyroidism and fibrous osteodystrophy in puppies.^[22] A commercially prepared (frozen or freeze-dried) raw food diet is one option for ensuring nutritional balance.

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, the specific need for taurine supplementation aside, "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."^[23]

Some proponents of raw diets recommend consultation with a veterinarian or animal nutritionist to verify that proper nutrients are being ingested,^[24] others dismiss the importance of AAFCO standards, claiming that AAFCO certification is not indicative of the quality of a diet.^[25]

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, and the chewing of bones and ligaments considered to provide numerous other health benefits.^[26]

The use of whole bone creates a risk of dental fractures,^[27] intestinal obstruction, gastroenteritis, and intestinal perforations.^[21][28] 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.^[29] 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,^[30][31] 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.

Bacteria, viruses and parasites

While the intense heat used in manufacturing pet food or cooking meat destroys any potential bacteria, raw meats may contain bacteria that are unsafe for both dogs and cats.<ref name=""O'Rourke"">Kate O'Rourke (15 January 2005). "Raw meat diets spark concern: Companion Animals (written 1 January 2005)". JAVMA News. American Veterinary Medical Association. Retrieved 7 January 2015. </ref> The U.S. government reported that in 2006, 16.3% of all chickens were contaminated with Salmonella.^[32] 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 O157:H7 was not tested for.^[33] 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. A contributing factor might be that racing greyhounds are typically fed raw meat classified as "not for human consumption", which may contain higher than normal levels of bacteria.^[34]

Raw feeders claim that the stomach enzymes and short intestinal tracts of dogs and cats allow them to handle harmful bacteria.^[35][36] There has been a reported case where two cats fed a raw diet developed salmonellosis and died as a result.^[9] 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.^[9] Bacteria proliferation in any meat can be reduced by following proper food safety practices such as defrosting meat in the refrigerator; harmful bacteria can be largely eliminated from meat by cooking.

Raw meats may also contain harmful parasites. As with bacteria, these parasites are destroyed during the heat processing of cooking meat or manufacturing pet foods. Some raw diet recipes call for freezing meat before serving it, which greatly reduces (but does not necessarily eliminate) extant parasites. According to a former European Union directive,^[37] freezing fish at -20 °C (-4 °F) for 24 hours kills parasites. The U.S. Food and Drug Administration (FDA) recommends freezing at -35 °C (-31 °F) for 15 hours, or at -20 °C (-4 °F) for 7 days.^[38] The most common parasites in fish are roundworms from the family Anisakidae and fish tapeworm.^[39] While freezing pork at -15 °C (5 °F) for 20 days will kill any Trichinella spiralis worm,^[40] trichinosis is rare in countries with well established meat inspection programs,^[41] 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.^[42]

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.^[43]

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".^[44] 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 and while 30 percent of the stool samples from dogs fed a raw food diet contained salmonella, none of the control dogs (commercial feed) 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 generalizability of their results due to the small number of dogs studied.^[45]

Because of the potential animal and human health risks, veterinarian organizations and public health agencies assert that the risks inherent in raw feeding outweigh the purported benefits.^[46] Despite such concerns, there is no known incidence of humans being infected with salmonella by cats and dogs fed a raw diet.^[47]

Commercial preparation

After the 2007 pet food recall, interest in homemade pet food (both cooked and raw) grew tremendously.^[48] As a result of that, several pet food manufacturers now offer frozen raw diet products for pet owners. Some consumers believe that many of the same issues they find with commercial pet foods exist with packaged raw diets, others use it due to its convenience and for products with AAFCO certification.

The commercial raw pet food market is estimated to be worth $169 million a year (2007 figures), less than 1% of total pet food sales figure in North America($18 billion). Growth is estimated at 23% per annum.^[49]

Many commercial raw pet food manufacturers now use High Pressure Pasteurization (HPP), a process that kills pathogenic bacteria through high-pressure. High Pressure Pasteurization is a USDA-approved food processing technique.

Veterinary position

Veterinary associations such as the American Veterinary Medical Association, British Veterinary Association and Canadian Veterinary Medical Association have warned of the animal and public health risk that could arise from feeding raw meat to pets and have stated that there is no scientific evidence to support the claimed benefits of raw feeding.^[44][46]

In 2007, The Sydney Morning Herald reported that the RSPCA Australia President Dr. Hugh Wirth has stated that veterinary associations in Britain and Australia make a "compromise" and advocate some feeding of raw bones to dogs.^[50] This contradicts the contemporaneous warnings put out by the BVA against feeding pets raw bones.^[51]

See also

• Raw foodism
• Paleolithic diet - A human diet based on a similar evolutionary rationale.

References

Further reading

• Billinghurst, Ian (1993). Give Your Dog a Bone: The Practical Commonsense Way to Feed Dogs for a Healthy Life. Lithgow, N.S.W.: I. Billinghurst. p. 320. ISBN 978-0-646-16028-3. 
• Lonsdale, Tom (2001). Raw Meaty Bones Promote Health. Dogwise Publishing. p. 389. ISBN 978-0-646-39624-8. 
• Billinghurst, Ian (2001). The BARF Diet: Raw Feeding for Dogs and Cats Using Evolutionary Principles. N.S.W. Australia: Ian Billinghurst. ISBN 978-0-9585925-1-2. 
• Lonsdale, Tom (2005). Work Wonders: Feed Your Dog Raw Meaty Bones (PDF). Dogwise Publishing. p. 118. ISBN 978-0-9757174-0-0. 

External links

Articles

• Raw Learning Information collected by Jane Anderson
• Raw Fed Dogs Feeding the way mother nature intended
• The beef over pet food Salon.com, January 2006
• Bones of contention Dogs Today Magazine, September 2006
• BARF: Bones And Raw Food Overview of the BARF diet and issues.
• Should Your Dog Eat BARF? VetCentric.com
• Raw vs. BARF: Waging an Imaginary War On the perceived differences between BARF and raw feeding
• Her Great Danes Eat It Raw San Francisco Chronicle SFGate.com, September 2003
• Trends in Home-Prepared Diets for Pets Weston A. Price Foundation
• Martin AN (June 2005). "How safe is a raw diet? Not very—and the facts are chilling: Ann Martin has spent her career taking on the pet-health establishment". Better Nutrition. 
• Love Me Tender January 2013
• Are Wisely-Chosen Bones and Gristle An Alternative To Frequent Dental Visits For My Pet ? January 2013