The cat’s needs for BARF diet on the other hand are very different from dogs because unlike most other carnivores, cats eat almost no vegetable matter as part of their regular evolutionary diets. Whereas animals like bears and dogs commonly supplement their diet of meat with fruits, berries, roots, etc when they can get them, cats feed exclusively on meat, usually freshly killed. Cats, including the great cats, have a genetic anomaly that prevents them from tasting sweetness that probably has an important part to play in their meat-only habits. In captivity, cats cannot (and should not) be adapted to a vegetarian diet because they cannot synthesize all the amino acids they need from plant material. Specifically this applies to Taurine, the lack of which causes the cat’s retina to slowly degenerate, causing eye problems and ultimately permanent blindness. This condition is called central retinal degeneration (CRD). Cow’s milk is a poor resource of taurine and adult cats are generally lactose intolerant. You can feed cats lactose-free milk and while it may be perfectly safe, is still not a substitute for meat. This contrasts with domesticated dogs, which commonly are fed a mixture of meat and vegetable products and have been adapted in some cases to a completely vegetarian diet.
Despite these proven and well known feline necessities, the majority of brand-name cat foods are primarily grain based, often containing large amounts of corn or rice and supplemented with meats and essential vitamins and these simply do not meet the nutritional requirements of cats but much less so a lactating or pregnant cat. In the case of the cat, which is an obligate carnivore and a hunter, the biologically appropriate diet is based largely upon animal derived foods. Basically, whatever nutrition can be derived from a whole fresh raw carcass – in its entirety – constitutes a biologically appropriate diet. Relative to size, domestic cats are very effective predators. They ambush and dispatch vertebrate prey using tactics similar to those of leopards and tigers by pouncing; they then deliver a lethal neck bite with their long canine teeth that severs the victim’s spinal cord, or asphyxiate it by crushing the windpipe. The domestic cat can hunt and eat about one thousand species—many big cats will eat fewer than 100. Although, theoretically, big cats can kill most of these species as well, they often do not due to the relatively low nutritional content that smaller animals provide.
Cats have highly specialized teeth and a digestive tract suitable to the digestion of meat. The premolar and first molar together compose the carnassial pair on each side of the mouth, which efficiently functions to shear meat like a pair of scissors. While this is also present in canines, it is highly developed in felines. The cat’s tongue has sharp spines, or papillae, designed to retain and rip flesh from a carcass. Cats also rely on bones as a major part of their diet for a variety of reasons including teeth cleaning and the myriad of benefits and nutritional attributes of bones as well as their psychological benefits. Cats are also known to munch on grass, leaves, shrubs and houseplants. They do not eat a lot in one sitting, but prefer to have it as a snack. Eating vegetation in this way may aid the cat’s digestive system and can prevent hairballs.