Thoughts and resources on the feeding of domesticated animals

- Kodiak Firesmith, 2010

My Own Opinion:

The vegetarian community is divided on the issue of feeding pets.  I cannot offer much original thought on the matter, as I'm still learning about the issue and developing my own opinions on it.  As it stands now, I am in the camp of those who have decided that the best realistic option currently is to provide a diet that is as close to an animal's natural diet as is possible.

Part of my own reasoning for becoming vegan was the comparison of physiological traits of an animal and it's diet.  Herbivores, obligate carnivores, and opportunistic omnivores all contain a series of physical traits common to a given diet.

Dental Traits

• Herbivores have sharp incisors, usually flat cuspids, and flat molars; this handles the large amount of fibrous vegetables in the herbivore diet.
• Obligate carnivores have full rows of pointy teeth, with little distinction between molars and cuspids in shape, but usually the cuspids form long fangs.  This is ideal for grabbing, killing,  tearing, and shredding meat, hide, and small bones.
• Opportunistic omnivores generally have varying degrees of the two above dental types, generally the incisors and molars of herbivores, with shorter versions of the carnivore-type cuspids.  Cuspid length varies quite a bit.

Intestinal Traits

• Herbivores have very long intestines and often have multiple digestion chambers with less acidity than an omnivore or carnivore.
• Obligate carnivores have a single highly acidic digestive chamber and very short digestive tract.
• Opportunistic omnivores have a single digestive chamber and medium length digestive tract.

Food procurement traits

• Herbivores have frames tailored for gathering plant matter, like a cow's grazing posture, or a giraffes long neck.
• Obligate carnivores have strong, protruding jaws that open very wide, and generally have sharp claws or talons, and fangs.  They generally are also fast, stealthy, and vicious.
• Opportunistic omnivores have a mix of these traits (think: monkey)

Dietary requirements & restrictions

• Herbivores handle meat consumption poorly due to long digestive path and low acidity, among other things.
• Obligate carnivores generally require nutrients like taurine in order to remain healthy.
• Opportunistic omnivores vary greatly in their requirements and restrictions.

Cats fit squarely into the obligate carnivore group.  Rabbits, rats, hampsters etc fit into the herbivore group.  Dogs fit into the opportunistic omnivore category.  (In case you were wondering about us humans, we're in the opportunistic omnivore category, and far toward the herbivore side in the opinion of this author.  This is because of our body's exceptionally poor handling of meat products)

Current Stance

Dogs: I believe that dogs can be fed a nutritionally adequate and healthful vegan diet thanks to modern science, and recommend Humane Society of the United States' own brand: Humane Choice dog food as the best option.  Were a dog to shun vegan dog foods, I'd recommend an organic & free range venison solution, like that of Evo.

Cats: I believe that there is not enough evidence to warrant the recommendation of a vegan cat food and currently feed my cats an organic & free range cat food.

Dogs

Dogs will hunt, kill, and eat animals naturally, as well as scavenge other kills.  Naturally, dogs express this behavior when they get the chance, but also will gladly eat most fruits and vegetables, including grasses.  Many groups are of the position that the nutritional needs of dogs can be met in a vegetarian manner.  There are many vegetarian dog foods on the market, and plenty of anecdotal evidence to their healthfulness, especially when compared to average dog food which is largely grain and animal renderings.

Cats

Cats will hunt, kill, and eat animals naturally.  Aside from synthetically produced taurine additives, cats cannot get their nutritional requirements in any foods other than other animals.  Average cat food actually uses this synthetic taurine as an additive to ensure that standard levels are maintained.  Regardless of the possibility of feeding cats a synthetic vegan diet, I cannot do so with mine.  I've opted instead to feed them only organically raised near-wild animal-based food.  I realize that this is inhumane to the animals killed for the food, and that it's resource intensive, this effectively makes me a hypocrite on some level, putting one animal before another, and I've accepted that.  I will likely continue to adopt cats in need of rescue for the rest of my life.

Further reading on this topic:

Wikipedia information on vegetarian cat food

Book excerpt on vegan food for dogs and cats

Vegetariandogs.com

Nutritional Requirements of Dogs - National Academies (PDF)

From the document:

Q:  Does my dog need to eat meat?
A:  Because dogs are descended from omnivores, they
are not strict meat eaters.  They are remarkably adapt-
able to a wide range of ingredients, texture, and form in
terms of what they will eat.  Though many dogs may
prefer animal-based protein, they can thrive on a vege-
tarian diet.  Regardless of whether the protein comes
from plant or animal sources, normal adult dogs should
get at least 10% of their total calories from protein.  Older
dogs appear to require somewhat more protein to maintain
their protein reserves, perhaps as much as 50% more.

Nutritional Requirements of Cats - National Academies (PDF)

From the document:

Q:  Does my cat need to have meat and/or fish products in its diet?
A:  Domestic cats are descended from strict meat-eaters, and their behavior reveals
their carnivorous nature.  When hunting, domestic cats will seek small prey such
as mice, birds, and insects.  They may even kill and eat a rabbit.  They will stop eating
a meal of commercial cat food and go off hunting if distracted by potential prey.  The
particular chemistry and structure of the cat’s gastrointestinal system is well-suited
to digesting and absorbing nutrients from animal-based proteins and fats.
Unsupplemented vegetarian diets can result in harmful deficiencies of certain essen-
tial amino acids, fatty acids, and vitamins.

Humane Society not only endorses a vegan dog diet, it's developed a vegan dog food marketed on their site:

Humane Choice Dog Food (ORGANIC!)