Veterinarian and Professor Andrew Knight on the best diets for our animal companions
Meat-Based Pet Food Despite the biological evidence, millions of people cling to the belief that it is somehow natural to feed their feline or canine companions commercial diets comprised of assorted body parts from a variety of animals they would never naturally eat. To these are added abattoir products condemned as unfit for human consumption, such as ‘4-D’ meat (from animals that are disabled, diseased, dying or dead on arrival at the slaughterhouse), cleverly disguised using names like ‘meat derivatives’ or ‘by-products.’
Unfortunately, fish have not evolved mechanisms to excrete modern oceanic pollutants such as mercury and PCBs, which accumulate in their tissues. Once exposed to air, fish are particularly vulnerable to bacterial putrefaction. Damaged or spoiled fish are also added to commercial pet foods.
Brands from countries such as the US also contain rendered dog and cat carcasses sourced from animal shelters. Similarly, toxic flea collars are not always removed. Unsurprisingly, a 1998 US Food and Drug Administration study detected the euthanizing solution sodium pentobarbital, which is specifically designed to kill dogs, cats and other animals, in 43 randomly-selected varieties of dry dog food.
To enhance palatability, dry food is sprayed with a combination of refined animal fat, lard, used restaurant grease, and other oils considered too rancid or inedible for human consumption, containing high levels of unhealthy free radicals and trans fatty acids. These oils provide the distinctive smell that wafts from a newly-opened packet of kibble.
Additional hazards include bacterial, protozoal, fungal, viral and prion contaminants, along with their assorted endotoxins and mycotoxins; hormone and antibiotic residues, particularly in brands from countries such as the US, where more of these chemicals are administered to livestock; and potentially dangerous preservatives, some of which have been banned in various countries.
Greed: A Powerful Force The desire of food industry executives to squeeze a few pennies more from ingredients that should rightly be condemned as unfit for consumption have effectively turned meat-based pet food into a vast, industrial dumping ground, filled with products no sane cat or dog would contemplate. Greed, however, is a powerful inspirational force, which led to the invention of ‘digest.’ According to the text 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.” So what, precisely, is this wonder ingredient? Digest is an industry euphemism for a soup of partially dissolved intestines, livers, lungs and miscellaneous viscera of chickens (primarily), and other animals, produced using various enzymes and acids. The precise ingredients are closely guarded trade secrets, which, in differing combinations, produce varying flavours. Batches considered to taste more like beef can magically transform a can of miscellaneous animal body parts into ‘Beef Stew,’ while those considered more ‘fishy’ may create ‘Ocean Whitefish.’
Vegan diets: healthy? Properly formulated vegan diets can provide a healthy alternative for both cats and dogs, eliminating the numerous hazards inherent within meat-based pet food. Vegan diets supply all required nutrients using only vegetable, mineral and synthetic sources. Each species requires particular dietary nutrients, after all, rather than specific ingredients. A growing number of manufacturers now supply vegan companion animal diets (see www.VegePets.info, ‘Suppliers’). Both complete diets and dietary supplements are available. The former offer convenience, while the latter provide a cheaper alternative for those wishing to add nutritional supplements to home-made diets. Recipes are available in books like Vegetarian Cats & Dogs (Peden, 1999) and Obligate Carnivore (Gillen, 2003), and from suppliers.
Unnatural behaviour? Well-meaning but mistaken animal guardians often resist vegan diets, believing that commercial meat-based diets allow greater expression of natural feeding behaviour. This claim warrants closer scrutiny.
When wild cats or dogs kill prey, they gorge as much as possible to prevent consumption by competitors. This is followed by uncertain periods of hunger. Yet, commercial meat-based diets comprise assorted body parts from animals that cats and dogs never naturally eat, heavily laced with unnatural additives of questionable safety. These are dispensed from tins or packets at predictable times daily, with kibble sometimes available around the clock. The result bears very little resemblance to natural feeding behaviour.
Guardians frequently microchip, vaccinate, de-worm, de-flea and de-sex their furry companions, and confine them indoors at night, because they correctly believe such steps are necessary to safeguard health. Why, then, do so many resist feeding healthy vegan diets to cats and dogs on the basis that it is ‘unnatural’?
The real reasons for this curious double standard probably arise from the deep-seated needs of these otherwise caring animal guardians to justify the suffering and death involved in past and present meat-based dietary choices, through maintenance of a belief that meat is natural or necessary.
Health effects The belief that cats, and to a lesser degree, dogs, cannot thrive without meat, remains widely held, even by veterinarians. However, a recent search of the bio-medical literature yielded only one study demonstrating an adverse effect in vegetarian cats. This diet was known to be nutritionally deficient.
On the other hand, at least ten scientific studies have demonstrated increased risks of a variety of diseases following long-term maintenance of cats and dogs on meat-based diets, including: kidney, liver, heart, neurologic, visual, neuromuscular and skin diseases, bleeding disorders, birth defects, weakened immune systems and infectious diseases (see www.VegePets.info, ‘Meat-Based Diets’). As with humans, rates of so-called ‘degenerative’ diseases such as obesity, cancer, heart and kidney disease are rising in cats and dogs to unnatural and disturbing levels and long-term exposure to unhealthy diets is the most common preventable cause.
In 2006 the first study of the health of a population of long-term vegetarian cats (most, in fact, were vegan), was published in the Journal of the American Veterinary Medical Association – one of the world’s leading veterinary journals. Most were clinically healthy, barring minor blood value changes in three cats, who were fed partly on table scraps.
Similarly, a 1994 study of a population of vegan (65%) and vegetarian (35%) dogs again found the vast majority to be in good to excellent health, particularly in lifetime vegans or vegetarians. Based on these large-scale studies and numerous additional reported cases, nutritionally-sound vegan or vegetarian companion animal diets appear to be associated with the following health benefits: increased overall health and vitality, decreased incidences of cancer, infections, hypothyroidism (an important hormonal disease), ectoparasites (fleas, ticks, lice and mites), improved coat condition, allergy control, weight control, arthritis regression, diabetes regression and cataract resolution.
Safeguarding health Nutritionally-sound vegan diets can meet all of the needs of cats and dogs, while avoiding the hazards inherent to commercial meat-based diets. Correct use of a complete and balanced nutritional supplement or complete diet is essential to prevent the nutritional diseases that will otherwise eventually occur, if certain dietary nutrients are deficient.
Changing to a vegan diet may also result in urinary alkalinisation, which increases the risk of urinary stones and blockages, especially in male cats. These can be life threatening. Hence, regular monitoring of the urine acidity of both sexes of cats and dogs is essential, perhaps fortnightly during any dietary transition, and at least every three months after stabilization. Urine can be collected from dogs using containers such as foil baking trays, and from cats using non-absorbent plastic cat litter available from veterinarians. pH (acidity) test strips are also available from veterinarians, although pH metres provide the most accurate results. The pH of cat and dog urine is normally 6.0 – 7.5. A variety of dietary additives listed at www.VegePets.info can correct alkalinisation, should it occur.
Vegan Diet Great patience and persistence may be required when altering diets, particularly for animals previously exposed to digest. Changes are best made gradually, e.g., by feeding a 90%/10% old/new dietary mixture for a few days, then 80/20%, and so on. Gradual changes also allow an appropriate transition of digestive enzymes and intestinal microorganisms, minimizing adverse reactions such as diarrhea. Guardians should demonstrate clearly 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 animals eat around new food at first. Having it in close proximity will help create the necessary mental association, as will mixing the food thoroughly, and the addition of odiferous (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. Fresh food should always be offered. The most important factors for transitioning difficult animals are gradual change and persistence. Using these principles, the most stubborn of cats and dogs have been successfully weaned onto healthy vegan diets.
Conclusions There are numerous incongruous and potentially hazardous ingredients in commercial meat-based pet foods. You might want to consider a nutritionally-sound vegan alternative. This would maximise the chances of good health and longevity for not only your cat or dog, but also, of course, our frequently mistreated, so-called ‘food’ animals!
Publisher’s Note: Below, listen to Prof. Andrew Knight’s passionate talk on Climate Change and Biodiversity Loss. For more of his incredibly informative videos, link here.
Prof. Andrew Knight Bio:
I am originally from Australia, and ever since helping launch Australia’s campaign against the live sheep trade to the Middle East in the early 1990s, I have tried to advocate on behalf of animals. For nearly a decade prior to 2012 I practiced veterinary medicine, mostly around London. In 2013 – 2014 I Directed the Clinical Skills Laboratory and taught animal ethics, welfare, veterinary practice management, and surgical and medical skills at one of the world’s largest veterinary schools in the Caribbean.
I have over 70 academic and 80 popular publications, an extensive series of YouTube videos, on plant-based companion animal diets, climate change and the livestock sector, invasive animal research, educational animal use, humane clinical and surgical skills training, and other animal welfare issues. I’ve delivered more than 170 presentations at conferences and universities internationally, and have have organized or chaired seven conferences and seminars. I regularly work with animal welfare charities to advocate for animals, and am frequently interviewed by the media. I have been honoured with 13 awards and 11 research grants, including the Society for Veterinary Medical Ethics Shomer Award, a University Values Award and the Humane Society Veterinary Medical Association Humane Achievement Award, all in 2019. I enjoy teaching, and was delighted to receive a University Student-Led Teaching Award in 2017. My informational websites include www.VegePets.info, www.HumaneLearning.info and www.AnimalExperiments.info.
I am now Professor of Animal Welfare and Ethics, and Founding Director of the University of Winchester Centre for Animal Welfare, an EBVS European and RCVS Veterinary Specialist in Animal Welfare Science, Ethics and Law, an American and New Zealand Veterinary Specialist in Animal Welfare, a Fellow of the Royal College of Veterinary Surgeons, and a Principal Fellow of Advance HE (formerly the Higher Education.
Publisher’s Note: For educational articles, presentations, reports and more, link to Prof. Andrew Knight’s website.
For Prof. Andrew Knight’s book “The Costs And Benefits Of Animal Experiments” link here.
Prof. Andrew Knight’s article first appeared in Lifescape Magazine. Knight A (2008). Fishy business? Lifescape, May, 74-76.
About Lifescape Magazine:
Lifescape was set up by Rajasana Otiende in 2005. It was a glossy monthly magazine aimed mostly at women who wanted to live a more cruelty-free, healthy, green and interesting life. The magazine covered fair trade fashion, cruelty-free and vegan beauty products, social issues, health, nutrition, home, travel and more. It was also the only vegetarian magazine on sale at British newsstands.
Each year Lifescape commended companies that were making a difference by producing cruelty-free cosmetics in its Beauty Awards. It also ran Food Awards for vegetarian or vegan, fair trade and organic foods which provided excellent options for people who ate with a conscience.
