Cats are not small dogs …
By now, we hope that you will agree that dogs and cats are different, and dogs have different dietary requirements than cats do. Unlike cats, which are true carnivores, and require a diet high on protein, dogs are more omnivorous and therefore require a diet lower in protein than cats do.
For the purpose of our discussion here, it serves no purpose to argue whether the correct canine classification should be “carnivore” or “omnivore”. We indeed believe that the correct definition is facultative carnivore – meaning “optional” or “discretionary”. We subscribe to the concept that a certain amount of carbs & fiber can be used by domesticated canines, and as such, a small amount of vegetables and fruit are included in the diet’s we supply to our fur customers. This concept in particular is widely controversial and a big point of debate and divergence between the “eastern” (prey model or meaty bone model) and “western” (biologically species appropriate model) philosophies that apply to canine nutrition.
First, cats must eat fresh food. Cats do not have the metabolic means to digest “ripe” food and get rid of any toxic by-products; instead, they have evolved very specific taste and scent capabilities that would prevent them from eating anything that is not fresh. This, in part, is what accounts for the “pickiness” of cats. They are evolutionary picky for good reason. When feeding a raw diet, this means that all of the cat’s food must be fresh. Of course, it can be frozen first and then defrosted, but cats should not be fed any “old” meat – you can save that for the dogs.
The natural diet of dogs could be higher in carbohydrates (see our article on the Carb Debate) than is the natural diet of cats, although neither has strict dietary requirements for carbohydrates. Dogs, unlike cats, can make one of the fatty acids called arachidonic acid from linoleic acid and therefore don’t require this in their diets.
Second, it is strongly recommended that cats eat every day. It is not wise to fast a cat for more than 24 hours, and especially if the cat is overweight! Due to their unique metabolism, cats can suffer from “hepatic lipidosis” if they do not receive adequate amounts of food. Thus, when switching a cat to a raw diet, one must be very careful that the cat eats something every day – even if that means mixing commercial food in with the raw food so the cat eats.
Cats have a dietary requirement for the amino acids arginine and taurine, whereas dogs do not. Vitamin A occurs only naturally in animal tissue; vitamin-A precursors such as beta-carotene are synthesized by plants. Dogs, unlike cats, can make their own vitamin-A from beta-carotene and therefore don’t require pre-formed vitamin A. We discuss these requirements in some detail further down.
Third, as stated above, cats do not have the capability to create taurine from methionine and cysteine, like dogs do. This means that a cat must ingest sufficient taurine in order to meet its taurine requirements. The excellent news is that taurine is found in virtually all meats, especially beef heart. By feeding a cat a raw diet, the cat should receive the best, most bioavailable form of taurine via its food. There is one proviso: grinding increases the surface area of the meat and thus exposes more of the “good stuff” to the air. This results in oxidation of taurine and a resultant decrease in overall taurine available to the cat. You will therefore notice that all of our frozen meals for cats include additional taurine for this very purpose.
Outlined below are just a few of the unseen, but still very real, biochemical differences between cats and dogs. Look these over and you will be even more convinced that cats are different!
- Vitamin A – Also called retinol, this vitamin is required at the cellular level by both cats and dogs.
- Cats – Process little or no enzymes that will break down the plant-produced carotenoids. Must eat preformed active Vitamin A (that is, Vitamin A that already has been converted from carotenoids to its active form by some other creature such as a mouse or rabbit). Here’s a good example of why cats are called strict carnivores … they need to eat some other animal in order to “borrow” its active Vitamin A!
- Dogs – Have enzymes in the lining of the intestine that can break down plant carotenoids and convert these into active Vitamin A.
- Niacin – An essential B vitamin (essential means must be eaten, can’t be made inside the body’s chemical factory.)
- Arginine – A building block for proteins, it is an amino acid. Arginine is vital to many of the animal’s internal chemical factory’s functions. No Arginine and the entire factory goes on strike!
- Cats – Are extremely sensitive to even a single meal deficient in Arginine and are unable to make their own Arginine within their chemical factory. Cats need lots of protein, and Arginine is involved in aiding the elimination of the protein waste products so the wastes don’t pollute the whole factory!
- Dogs – Are not very sensitive to low levels of Arginine in their diets and produce enzymes internally that can aid production of Arginine.
- Taurine – An amino acid that is not built into proteins, but is distributed throughout most body tissues. Taurine is important for healthy functioning of the heart, retina, bile fluid and certain aspects of reproduction.
- Cats – Must eat preformed Taurine, in other words, they must “borrow” the Taurine from somewhere else. And since it is not found in plant tissues, cats must consume meat to obtain Taurine. Therefore, Taurine is essential in the diets of cats. Here again, meat has to be supplied to the factory so the Taurine can be extracted for its many uses.
- Dogs – Make their own in their internal chemical factory.
- Felinine – It is a compound made from a sulfur amino acid (SAA) called Cysteine.
- Cats – Have a much higher requirement for SAA than other Mammalia and are the only creatures to manufacture the Felinine chemical. Felinine’s role in the overall function of the chemical factory is unknown, but like most factories whose wastes generate offensive odors, any Felinine present in the male cat’s urine alerts the neighbours that the factory is up and running’!
- Dogs – Don’t know and don’t care what this stuff is.
- Dietary Protein
- Cats – If fed a perfectly balanced and 100-percent digestible protein in a diet, the cat will use 20 percent of that protein for growth metabolism and 12 percent for maintenance. Simply put, cats need more protein in their diets than dogs do.
- Dogs – If fed a perfectly balanced and 100-percent digestible protein in a diet, the dog will use 12 percent of that protein for growth metabolism and only 4 percent of that protein for maintenance. Simply put, dogs need less protein in their diets than cats.
- Arachidonic Acid – An essential fatty acid that plays a vital role in fat utilization and energy production.
- Cats – Cannot make their own Arachidonic Acid even in the presence of adequate linoleic acid. The reason cats can’t make Arachidonic Acid from linoleic acid is because the cat’s chemical factory (liver) contains no delta-6-desaturase enzyme to convert linoleic to Arachidonic. Tell your cat owning friends about this one. Tell ‘em about the cat’s lack of liver delta-6-desaturase enzyme and they’ll think you’ve got a Ph.D. in biochemistry!
- Dogs – Can make their own Arachidonic Acid if they consume enough linoleic acid by eating proper fats. Therefore, we can say that Arachidonic Acid is not an essential fatty acid for dogs.
- Fasting and Starvation
- Cats – Do not mobilize fat reserves for energy very efficiently and, in fact, break down non-fatty body tissues for energy. This upsets the internal chemical factory and can lead to a very dangerous feline disorder called hepatic lipidosis. Never put a fat cat on a starvation diet, it might just put the entire factory on strike and out of business.
- Dogs – Can tolerate prolonged fasts and utilize fat reserves for energy.
Now you have an insight into some of the invisible goings-on in your master, the cat. It should be obvious that a high quality, meat-based diet is imperative to a cat’s wellness. There are no vegetarian diets for cats! Both benefit from a biologically species appropriate raw diet.
What are the key messages?
As noted by the WALTHAM Centre for Pet Nutrition, cats cannot just be considered small dogs, and by now, you will agree. They are different species with very different dietary requirements.
There are some key differences in gastrointestinal physiology between dogs and cats (see: Nutrient Requirements of Dogs and Cats (Nutrient Requirements of Animals), NRC (Amazon) 1:
- The cat’s small intestine is shorter than the dog’s (even when corrected for overall body length), with a shorter transit time;
- The cat has a slightly less well-developed caecum than the dog;
- The gastric mucosa in the two species differs;
- The dentition of the dog includes molars for crushing plant material, whereas the cat lacks these teeth.
Implications on Dietary Requirements?
Dogs and cats have distinctly different dietary requirements. The cat is an obligate carnivore whereas the dog is more inclined to be an omnivore. The cat’s absolute requirement for nutrients derived from a meat-based diet arises from metabolic peculiarities in this species.
The nutritional peculiarities of the cat were summarised in a WALTHAM review by Legrand-Defretin in 1994 2:
- The cat has a higher requirement for dietary protein than the dog;
- Taurine is an essential nutrient for the cat, and must be present in the diet. The cat has a lower capacity to synthesise taurine than the dog and cannot meet its taurine requirement from dietary sulphur-containing amino acids;
- The cat cannot synthesise sufficient nicotinic acid from tryptophan;
- The cat is unable to convert carotene to retinol and, therefore, cannot satisfy its vitamin A requirements with a herbivorous diet;
- The cat cannot convert sufficient linoleic acid to meet its requirement for arachidonic acid;
- The cat seems to be unable to cope with high levels of carbohydrate in its diet and appears to be in a constant state of gluconeogenesis;
These differences underpin the importance of formulating diets, including biologically species appropriate raw diets, specifically designed to meet the nutritional needs of cats and dogs. Worldwide, research is still ongoing and the nutritional guidelines for both cats and dogs are constantly being refined and updated (see our post about The Fallacy).
Additional Articles and Videos
Good articles & videos for further reading can be found here:
- How to Win the Healthy Food Battle with Your Fussy Feline by Dr. Becker … Part 1 (Ref) and Part 2 (Ref);
- Starter Guide for Cats [here] by Raw Feeding Rebels – a site dedicated to raw feeding cats (requires Adobe PDF Reader);
- Raw Feeders: Why Are You Feeding Your Dogs Like Cats? By Dana Scott from Dogs Naturally Magazine (DNM).
Getting Your Cat to Eat Healthier by Dr Karen Becker … Part 1, and;
References and Research
- 1.Sutton SC. Oral Anatomy and Physiology in the Companion Animal. In: Advances in Delivery Science and Technology. Springer US; 2012:59-68. doi:10.1007/978-1-4614-4439-8_4