Vegetarian Companion Animal Diets
http://tinyurl.com/vegepets-summary
Andrew Knight BSc. (Vet. Biol.), BVMS, MRCVS
Veterinarian
Updated: 20 May 2008
The enormous death and suffering inflicted upon approximately fifty billion chickens, pigs, sheep, cows, and other animals, both intensively and extensively farmed, who are slaughtered annually, and upon millions of intensively farmed or wild-caught fish, in order to fulfill the desire of some human beings for meat, has been thoroughly documented; as have the deleterious environmental impacts of both intensive and extensive animal farming (www.VeganOutreach.org provides extensive, thoroughly-referenced information on these issues).
It is because of the ethical concerns of a growing population of vegetarian animal guardians, and because of medical conditions such as allergies which are caused by beef, lamb and other meat-based dietary ingredients, that vegetarian pet food brands were first developed. However, vegetarian companion animal diets remain the subject of controversy, which is exacerbated by ignorance of the health and nutritional issues involved, including among veterinarians and other experienced animal carers.
Health hazards of commercial meat-based diets
The health hazards to dogs and cats (and, of course, to ‘food’ animals) that are inherent in commercial meat-based companion animal diets are extensive, and difficult to avoid. These diets provide a vast industrial dumping ground for slaughterhouse waste products, 4-D meat (from dead, dying, diseased or disabled animals), old or spoiled supermarket meat, large numbers of rendered dogs and cats from animal shelters, old restaurant grease, complete with high concentrations of dangerous free radicals and trans fatty acids, and damaged or spoiled fish, complete with dangerous levels of mercury, PCBs and other toxins. The combined results are rendered so delicious to cats and dogs by the addition of ‘digest’ - a soup of partially dissolved chicken entrails - that more than 95 % of US companion animals subsist primarily on commercial meat-based diets (Perry, 1996), generating in excess of $11 billion annually for the US pet food industry (API, 2002).
The pathogenic bacteria, protozoa, fungi, viruses and prions, and their associated endotoxins and mycotoxins, and the hormone and antibiotic residues and dangerous preservatives common to commercial meat-based diets, also present important hazards to the health of our companion animals.
Diseases
described in the scientific literature following long-term maintenance of cats
and dogs on commercial meat-based diets include kidney, liver, heart, neurologic,
visual, neuromuscular and skin diseases, bleeding disorders, birth defects,
immunocompromisation and infectious diseases (DiBartola
et al. 1993, Dow et al. 1989, Freytag et al. 2003 and
Strieker et al. 1996).
As a practicing veterinarian I agree that so-called degenerative diseases such
as cancer, kidney, liver and heart failure are far more common than they should
be, and that many are most likely exacerbated or directly caused by the numerous
hazardous ingredients of commercial meat-based diets for cats and dogs. Kidney
disease, for example, is one of the top three killers of companion animals, and
is exacerbated by the extra load placed on the kidneys by the high protein
content (Di Bartola et al., 1993) and poor quality ingredients of most
meat-based commercial diets. Left untreated, kidney disease may result in the
systemic buildup of toxins, leading to loss of appetite, uremic poisoning,
vomiting, neurological disorders, and death. The serious and potentially-fatal
disease of hyperthyroidism in cats first surfaced in the 1970s, when canned food
products appeared on the market, and may be related to excessive dietary iodine
levels (Smith, 1993).
Vegetarian companion animal diets
On the other hand, health benefits of vegetarian diets appear to include increased overall health and vitality, decreased incidences of cancer, infections, hypothyroidism, ectoparasites (fleas, ticks, lice and mites), improved coat condition, allergy control, weight control, decreased arthritis, diabetes regression, improved stool odor and cataract resolution (Gillen 2003, Peden 1999, PETA 1994).
Dogs may be biologically classified as omnivores, due to their ability to subsist on a mixed diet of animal and plant-based material in their natural environments. In contrast, cats are classified as obligate carnivores, because their evolutionary anatomical, physiological and biochemical adaptations to a carnivorous lifestyle prevent them from deriving substantial benefit from the available plant-based material in their natural environments. Both wild cats and dogs do consume plant material, primarily sourced from the gastro-intestinal tracts of their consumed prey.
However, despite widespread prejudice against vegetarian pet food, even amongst (ill-informed) veterinarians and experienced animal carers, there is no scientific reason why a diet comprised only of plant, mineral and synthetically-based ingredients cannot be formulated to meet all of the palatability, nutritional and bioavailability needs of the species for which they are intended. In fact, several commercially-available vegan (no animal product) pet diets claim to do so, and have jointly supported a healthy population of thousands of vegan cats, dogs and ferrets (who are also naturally carnivorous) for many years (Weisman, 2004). However, sound quality control procedures, including regular laboratory nutritional analysis, should be implemented, to ensure products consistently meet these requirements.
Safeguarding health
Correct use of a complete and balanced nutritional supplement or complete diet is essential to prevent cardiac or other diseases and to safeguard the health of vegetarian companion animals. Regular urine pH monitoring is also important to detect the urinary alkalinization, with its consequent potential for urinary stones, blockages and infections, that may result from a vegetarian diet in a small minority of cases. Urinary alkalinization may be corrected via dietary acidifiers such as asparagus, peas, brown rice, oats, lentils, garbanzos, corn, Brussels sprouts, lamb’s quarters (the herb Chenopodium album, also known as pigweed), most nuts (except almonds, coconuts and macadamia nuts), grains (not millet), and wheat gluten. More serious cases may require vitamin C, methionine, sodium bisulfate or ammonium chloride supplementation. If urinary blockages are a problem, dietary magnesium content should be minimized and urine production increased via dietary salt supplementation (unless heart disease is present).
Changing to a vegetarian diet
The fixation of some cats or dogs to meat-based commercial brands to which they have become accustomed is primarily due to the addition of ‘digest,’ the industry euphamism for partially digested chicken entrails. According to Small Animal Clinical Nutrition, “Digest is probably the most important factor discovered in recent years for enhancing the palatability of dry food for cats and, to a lesser degree, dogs.” (Lewis et al., 1987).
Consequently, considerable patience and persistence may be required when altering diets, particularly of fussy cats. In difficult cases it may first be necessary to withhold all food (not water!), for one day. This will stimulate the appetite without harming the pet. It may be necessary to change the diet gradually, e.g. by using 90 % old and 10 % new diet for a few days, then switching to 80 % and 20 % for a few more days, thereby transitioning to the new diet over several weeks, or even longer if necessary. A gradual change is more acceptable behaviorally in difficult cases, and also allows an appropriate transition of digestive enzymes (to the extent possible) and intestinal flora (bacteria), thereby minimizing the chance of gastrointestinal reactions such as diarrhea.
Guardians should demonstrate by their behavior that they consider the new diet just as edible as the old (without possibly warning or alarming their pet by making a fuss). They should not be concerned if their pet eats around the vegetarian food at first; just having it in close proximity to the other food will help the pet make the necessary mental association. Mixing the food thoroughly may help, as may the addition of odiforous (the sense of smell is very important) and tasty additives, such as nutritional yeast, vegetable oil, nori flakes and spirulina. Gently warming the food may also help. Guardians should remove uneaten food and offer only fresh food.
The most important factors for transitioning difficult pets onto a vegetarian diet are gradual change and persistence. Using these principles, the most stubborn of cats and dogs have been successfully weaned onto healthy vegetarian diets. Vegetarian pet food recipes may be obtained from Peden (1999) and Gillen (2003) and from suppliers www.VegePet.com and www.VeganCats.com, and in Europe from www.aminews.net.
· Animal Protection Institute(API). What is REALLY in your pet's food?: you may not want to know. Revised 29 Jan. 2002. abc12.com WJRT-TV/DT. 17 May, 2004. http://abclocal.go.com/wjrt/news/051004_CO_r2_pet_food.html.
· DiBartola SP, Buffington CA, Chew DJ, McLoughlin MA, Sparks RA. Development of chronic renal disease in cats fed a commercial diet. J Am Vet Med Assoc. 1993 Mar 1;202(5):744-751.
· Dow SW, Fettman MJ, Curtis CR, LeCouteur RA. Hypokalemia in cats: 186 cases (1984-1987). J Am Vet Med Assoc. 1989 Jun 1;194(11):1604-8.
· Freytag TL, Liu SM, Rogers QR, Morris JG. Teratogenic effects of chronic ingestion of high levels of vitamin A in cats. J Anim Physiol Anim Nutr (Berl). 2003 Feb;87(1-2):42-51.
· Gillen, J. 2003. Obligate Carnivore. Seattle, WA: Stein Hoist Books.
· Lewis L., Morris M., Hand M. Small Animal Clinical Nutrition. 3rd Edn. Topeka, KS, US: Mark Morris Associates. 1987:2-3.
· Peden J. 1999. Vegetarian Cats & Dogs. 3rd Edn. Troy, MT: Harbingers of a New Age.
· People for the Ethical Treatment of Animals (PETA). Dog health survey. Unpublished. 1994. http://www.helpinganimals.com/h-vegcat-survey.html, 12 Aug. 2004.
· Perry T. What's really for dinner?: the truth about commercial pet food. The Animals' Agenda. 1996. Nov. - Dec. http://www.preciouspets.org/truth.htm.
· Smith C.A. Research roundup: changes and challenges in feline nutrition. J Am Vet Med Assoc. 1993;203:1395-1400.
· Strieker MJ, Morris JG, Feldman BF, Rogers QR. Vitamin K deficiency in cats fed commercial fish-based diets. J Small Anim Pract. 1996 Jul;37(7):322-6.
· Weisman E. Personal communication to Andrew Knight re: Evolution Diet vegan pet food. 24 Feb. 2004.
