Pet
Food
Review

BARF (Biologically Appropriate Raw Food)

(see also: The case against BARF)

The BARF (“Bones and Raw Food” or “Biologically Appropriate Raw Food”) diet is a system of feeding championed by Australian veterinarian Dr. Billinghurst.

The philosophy behind using BARF is that the diet a dog or cat evolved to eat - over many millions of years of evolution - is the best way to feed it.

If you want to feed your dog BARF, it means not feeding your dog cooked and or processed food. That is, not feeding your dog a diet based on cooked grains. Artificial grain based dog foods, it is claimed cause innumerable health problems.

Advocates of raw diets claim that the diet has been tested positively for centuries on wild dogs, and that the increase in allergies, dysplasia, and other health conditions is as a result of dogs being fed commercial dog food.

Commercial dog food fans point to the millions spent each year on testing products. They believe that commercial dog food contains all of the nutrients that a dog needs to grow and be healthy. Also that since the BARF diet is complicated, many people do not properly understand or use it appropriately.'

Raw feeding advocates believe point to the intense heat used to process commercial pet food which can reduce nutrient values. Studies with rats apparently showed that the digestibility of amino acids in cat food is changed significantly by heat processing. Taurine, an essential amino acid for cats, is reduced or eliminated in heat processing. Pet food manufacturers must add taurine supplements to cat food, which it is claimed by Barf proponents is generally unnecessary in a raw diet.

A pet on a Barf diet will eat as varied a raw diet as possible, with lots of raw meaty bones, e.g. chicken wings, chicken necks, rabbit, oxtail, minced meats, lamb shanks, eggs and their shells, liver, heart, fish, yoghurt, veg (pulped), fruit, garlic, etc.

Health benefits are claimed for this type of diet:

• Reduced doggy odour.

• Naturally cleans teeth - no need for toothbrushes, de-scaling jobs, helps prevent gum disease.

• The time it takes for a dog to chew a raw meaty bones give their stomach time to get the acids moving.

• Produces firmer stools with reduced quantity.

• Can reduce vet bills (healthier dogs)

• Economical to feed in comparison to commercial dog foods.

• Mirrors what nature intended them to eat in the wild.

• Puppies develop at a more appropriate rate and quick growth spurts are avoided. A GOOD breeder will want to stop fast growth in any pup.

• The ripping and chewing involved in eating raw meaty bones develops the jaw, neck, and shoulder muscles of a dog.

• Better weight control which helps to reduce the symptoms of arthritis and obesity.

  
  There is plenty of advice on the web regarding feeding of puppies, kittens and adult pets on a raw food diet (a Google search for BARF brought up 4 million references) if this is something that interests you.

It would seem however that neither the American Veterinary Association nor the British Veterinary Association endorses the health benefits of raw food. Both organizations caution that animals fed raw meat run the risk of contracting food-borne illnesses. The BVA declares that "there is no scientific evidence base to support the feeding of raw meat and bones," and warns humans they risk exposing themselves to bacteria like salmonella."

For a basic introduction to RAW feeding and home cooking for your pet you could do worse than look at the excellent set of articles entitled:

Have Dinner In (An Introduction to Home-Prepared Diets for Dogs)
Articles by Mary Straus published in the Whole Dog Journal, April 2007

The case against BARF

Ann Wortinger LVT, VTS (ECC)of Michigan Veterinary Specialists has written and lectured extensively within the US on the subject. The following is a transcript from an American Veterinary Conference in 2006 where Ms Wortinger spoke and sought to address what she considers certain myths concerning raw feeding.

INTRODUCTION
It is generally accepted that dogs were domesticated from wolves; the period of this evolution ranges from 10,000-135,000 years ago. Accordingly, some recent DNA research shows that this occurred in stages in different areas, not all dogs breeds came from the same wolf or from the same geographic area.¹ The primary ancestor of the domestic cat is believed to the African wild cat, Felis libyca. Domestication started for cats much later then it did for dogs, ~8,000 years ago with full domestication taking place only 4,000 years ago.² The time difference is reflective in what these animals were domesticated for, dogs were hunters, cats were vermin killers on the farms.

As we evolved from a hunting society to a farming society, our needs changed also.
With this history in mind, we need to look at what food these animals have consumed since they joined us in our homes. Dogs did not continue to hunt and eat raw foods once domesticated; they primarily ate our leftovers and scraps. Since we have not consumed a raw food diet since fire was discovered, our dogs did not eat raw food either. Since cats were domesticated for their ability to control small vermin, they have continued to eat a raw food diet for a much longer period of time.

MYTH: Raw food diets are nutritionally superior to processed diets, and is “what nature intended dogs and cats to eat”.
There is no scientific evidence showing that raw food diets are nutritionally superior to processed foods. All processed foods are required to conform to AAFCO (American Association of Feed Control Officials) standards for sale in the United States. These standards can be met in one of two ways. The food can be “formulated” to meet AAFCO standards, or feeding trials can be done. Feeding trials are the preferred method of substantiating AAFCO certification.³ This takes into account not only nutrient content, but nutrient loss due to processing and digestibility.

Raw food diets overall are not marketed as “complete and balanced” and therefore not need to meet AAFCO standards. Some of the frozen diets however are marketed as “complete and balanced” and have AAFCO statements on the labels, but have not undergone feeding trials. The claim is that these diets are “complete and balanced” over a period of time, but not for each meal. There are three main types of raw food diets.

Commercially available complete raw food diets. These diets are intended to be complete and balanced without the need for additional supplements. They are typically sold in frozen form.

•Homemade complete raw food diets, many recipes for homemade raw food diets are available in books, article and on the Internet. These diets expect the owner to balance the diets out in the long term as each meal is not in itself balanced.

•Combination diets. These consist of commercially available mixes of grains and supplements. This mix is in turn combined with raw meat. (4)

Granted, raw food diets may be nutritionally superior to some commercially processed foods. Those would be the poor quality foods that have not gone through feeding trials, use lower grade ingredients, and have high cereal contents. Feeding any premium quality food would show an improvement just due to the increased quality of the ingredients used.

Since raw food diets have not gone through feeding trials, it is difficult to know if they are nutritionally balanced or not. One study has been done looking at the nutrient content of a variety of raw food diets, both home prepared and commercially available. None of the diets studied were balanced, and all had nutrient deficiencies or excesses. These deficiencies and excesses may have been balanced out in the long term, but this is not guaranteed. (4)

Pet food manufacturers know what changes occur with their foods with the various processing methods, and supplement as needed to maintain optimum nutrient levels. As with any science, we continue to discover every day new ways to use diet to modulate various disease or conditions-and the manufacturers continue to change and improve their foods.

MYTH: Domesticated species tolerate bacterial contamination in food without problems, even if they are pediatric, geriatric, or critically ill animals.
There is not scientific evidence to support this claim, and in fact three studies have found either bacterial contamination in the food or dishes, or death related to pathogenic bacteria directly related to the diet being fed.( 4, 5, 6)

The study looking at nutrient content of the diets also looked at microbial analyses. One of the five diets yielded growth of E. Coli 0157:H7. (4) This strain of E Coli has been connected to E Coli infection in people, and is one of the more pathogenic strains.

Another study presented in JAAHA reported two cats presenting for necropsy that died from septic Salmonellosis. In one of the cases it was directly traced back to the raw food diet fed. The two cases were 9 months apart in presentation, but from the same household. Healthy adult cats appear to have high immunological resistance to the development of clinical Salmonellosis. Cats that are immune compromised or otherwise ill would be at increased risk of infection due to contaminated food stuffs. (5)
Animals that are not sick themselves can also pose a public health concern due to shedding of bacteria into the environment. There are a number of bacteria that can be found on raw meat and transmitted to animals and subsequently to their owners or others in contact with the animal or their stool.

20-25% of poultry carcasses intended for human consumption test positive for Salmonella organisms, the raw meat used for feeding dogs is even more frequently contaminated. Most raw poultry is also contaminated with Campylobacter species, primarily Campylobacter jejuni, so food borne infection is highly probable for dogs fed raw chicken.

Shiga toxic Escherichia coli strains are routinely isolated from fresh ground hamburger. Escherichia coli 0157 has been identified in dog feces.
Yersinia enterocolitica, can frequently be isolated from raw meat, especially pork. As much as 89% of the commercially available raw meats may be contaminated with this organism.

Numerous food-borne parasitic infections can also affect dogs and cats. Feeding raw fish can result in infection with a variety of organisms including Diphyllobothrium latum, the fish tapeworm; Opisthorchis tenuicollis, a trematode that infects the bile duct, pancreatic ducts and small intestines; Dioclophyme renale, the giant kidney worm; and Nanophyetus salmincola, the vector for Neorickettsia helminthoeca, the agent responsible for salmon poisoning in dogs. (6)

Dogs routinely fed raw meat are commonly infected with the protozoan Sarcocystis spp., and infected dogs may excrete sporocysts in their feces and contaminate the environment. Dogs can become infected with Toxocara canis and with the raccoon ascarid, Baylisascaris proconis as a result of eating raw meat. Infected dogs can develop enteritis and shed infective eggs into the environment. In humans these two parasites cause visceral larval migrans. Dogs are also susceptible to infection with Trichenella spiralis whose larvae in found encysted in meat. Undercooked or raw pork is occasionally contaminated with this parasite. (6)

MYTH: Raw food diets improve the health of their pets
The primary claim from raw food proponents is that this diet improves the health of their pets. While this is fairly nebulous and hard to prove, very few medical conditions can be directly traced back to nutrition.

On average a wolf in the wild only survives to 8 years old, wolves in captivity can survive up to 16 years. Most deaths are attributed to predation, disease and starvation. As Darwin showed us, life in the wild is survival of the fittest. An animal with many of the diseases we treat for commonly in small animal medicine would not survive in the wild. That, to our pets would be the benefit of domestication. Until fairly recently, we did not have the medical knowledge to treat these conditions either, but as human medicine progresses, so does veterinary medicine.

It would be presumptuous to think that the conditions that we see and treat our cats and dogs for do not exist in the wild, and that this is solely due to the diet they consume. Furthermore, what would be the hunting ability of many of our current breeds? Could a Persian administer a cervical bite to a mouse, or is their breeding induced malocclusion too severe to do this? What are the chances that a Yorkie would be able to catch and kill anything to eat, and considering the variety of foreign objects that a Labrador eats, would it be able to find the right food to kill and eat?

MYTH: Uncooked food is more easily digested because it contains enzymes that cooking destroys.
Some nutrients are destroyed by heat, but not all heat-sensitive nutrients are eliminated during cooking. This is dependent on what the nutrient content of the food was initially and how the food is processed, stored and cooked. (7)

Heat can also affect proteins. Proteins can be “denatured”. Their physical and chemical properties can be changed or altered. This happens with egg whites when they are cooked, the albumin becomes denatured and easier for the body to digest. Some proteins in meat also exist as enzymes, proponents of raw food diets contend that these enzymes become inactive when the meat is cooked. These proteins would also become inactive in the stomach when they meet up with the digestive enzymes. There are also other enzymes that are resistant to digestion (digestive enzymes) and may or may not be affected by stomach acid or heat from cooking. For the enzymes that are affected by heat, there is little evidence to suggest that they are more beneficial to animals that eat them raw. (7)

Due to the cellulose layer found in all plant based compounds, digestibility of these nutrients is difficult until the cellulose layer is broken down. This can be accomplished either through chewing, grinding of the food or cooking. Plant based materials are the primary source of carbohydrates for the body; these carbohydrates in turn are used for glucose production. If insufficient carbohydrates are available for energy, the body can also use glucogenic amino acids or glycerol from fats. If adequate dietary carbohydrates are not available, amino acids will be directed away from muscle growth, fetal growth and milk production to be used for glucose production. (3)
As carbohydrates are heated or cooked with water the starch contained within the cells undergoes a process called gelatinization. The greater the degree of gelatinization, the greater the degree of digestibility. The central nervous system and the red blood cells required glucose for their energy needs. Glucose consumed in excess of energy needs can be stored as glycogen. After glycogen stores are filled, any extra carbohydrates are converted into long-chain fatty acids and stored as fat. (3)

CONCLUSION
Since feeding trials have not been done on the majority of raw food diets, their nutrient content, digestibility and supplementation levels are for the most part unknown. By using raw meats, clients are leaving their pets and themselves open to bacterial and parasitic infection from possibly tainted meats. And there is no guarantee of improved health, what are the options in treating these pets?

First and foremost, do not ostracize these clients; most people opting to feed a raw food diet are conscientious owners looking to do the best thing for their pets. They, unfortunately, do not have a nutritionist in the kitchens. Most importantly, try to get them to cook the food being fed to their pet-this will at least address the bacterial and parasitic problems. Find out what they don’t like about commercially available diets, if they are misinformed on any issues gently guide them in the right direction. If clients insist on continuing to feed raw food diets, or homemade cooked diets, recommend 2-4 yearly visits for complete physical exams and blood screens to detect any problems before they become severe.

References
1) Derr, M: DNA identifies dog breeds with 99% accuracy. New York Times News Service. May 20, 2004
2) Oates, JC: Domestication. Natural History Museum of Los Angeles County. www.lam.mus.ca.us/cats
3) Hand MS, Thatcher CD, Remillard RL, Roudebush P: Small Animal Clinical Nutrition IV. Topeka, KS, Mark Morris Institute, 2000
4) Freeman LM, Michel KE: Evaluation of raw food diets for dogs. JAVMA 218 (5): 705-709, 2001
5) Stiver SL, Frazier KS, Mauel MJ: Septicemic Salmonellosis in two cats fed a raw meat diet. JAAHA 39(6): 538-542, 2003
6) LeJeune JT, Hancock DD: Public health concerns associated with feeding raw meat diets to dogs. JAVMA 219(9) 1222-1224, 2001