Cat’s food

Of all our domestic animals, the cat is the only truly carnivorous one. Its digestive system is “programmed” for a 28-hour feeding cycle, so a cat can perfectly well eat rarely — once every 28 hours. Living alongside people has changed that: where there is food available at all times, cats will eat a great deal more often. Cats are extremely conservative about their food. Smell, texture (solid, crumbly, liquid) and taste decide which food a cat will choose; noise, light, the dish, and the presence or absence of a person or another animal nearby decide how much of it the cat will eat. These fads have a firm physiological reason behind them: cats are far more susceptible to poisoning than either people or dogs. A cat is capable of starving itself to death with food in front of it, if that is food it flatly refuses to eat! Which is to say that its self-restraint at the bowl overrides even the instinct of self-preservation. Neither a human nor a dog would allow itself such a luxury. Keep the fact in mind when you set about accustoming your cat to a new food.

RATE OF GROWTH

Very briefly: cats eat the most at the age of 150-160 days (5 months), and the period of fastest growth comes to an end at 200-220 days (7 months).

ENERGY

The calorie content of the food matters particularly for cats, because protein can only be absorbed when enough energy comes with it. Put plainly: if you give a lot of meat, you also need to give a lot of fat, or the meat will not be digested. For adult cats, 70 kcal per kilogram of body weight is recommended.

WATER

Water is one of the most important conditions of a cat’s good health, and at the same time one of the needs most often overlooked. Enough water will help the cat avoid disease of the bladder, will flush the toxins out of the body, will keep the appetite in order and will cleanse the system generally. A cat needs 60-80 ml of water per kilogram of weight. It takes water in with its food and as a drink. Water is also a by-product of metabolism, of the metabolism of fat in particular. A cat on wet food can manage without drinking: a cat fed on Whiskas^(r) or kitekat^(r), for instance, gets 80-90% of its liquid requirement from the food, whereas dry food supplies only 10%. Cats on a dry or semi-dry ration must always be given water as well. How much liquid a given animal needs is individual, and depends on a great many things — the temperature of its surroundings and of its body, how active the cat is, the state of its health and so on. See to it that the cat has access to clean water at any moment (milk is no substitute for water, even when it causes no diarrhoea). If your cat has a craving for milk, offer it one of the special milk drinks low in lactose — Whiskas Milk Plus, for example — rather than cow’s milk, since adult animals lose the ability to digest lactose. Try to change the water in the bowl at least three times a day.

PROTEIN

Cats need more protein than other species do. A healthy animal requires 2 g of high-quality protein a day for every kilogram of its weight — about 100 g of good beef. The quality of a ration is usually judged by its energy density: the rations considered best for adult cats are those in which protein accounts for no less than 21% of the total calories. Research has established that a cat’s protein must also supply the amino acid taurine, to guard against disease of the eyes. Firms producing cat food are advised to include no less than 0.1% taurine in it (0.1 g per 100 g of protein). This too follows from the particular way a cat’s metabolism works.

FATS

Besides fuelling activity, fat matters to a cat as the thing that lets other nutrients be absorbed. About 60% of the total energy of the ration should come from fat. A diet containing 14-60% fat (on a dry-matter basis) is considered normal. It should be borne in mind, though, that cats who live inactive lives can grow obese, exactly as people do. There is a further danger hidden in this recommendation: if a diet rich in fat is not backed up with vitamin E, steatitis may develop (“soap stones” in the intestine). The fat in the ration should also contain no less than 1% linoleic and 0.1% arachidonic acid. Many illnesses go with a weak appetite or none at all, and the cat then takes in less of the nutrients and energy it needs. In such cases, where nothing directly rules it out, adding extra fat to the ration is justified, since the share of protein has to be reduced and the lost energy made up with fats and carbohydrates.

CARBOHYDRATES

Carbohydrates — pasta, bread, sugar, starch, cellulose — are not obligatory in a cat’s ration, but they are comparatively cheap, and can be regarded as a cheaper source of energy than protein or fat. Starchy foods such as potato have to be cooked (boiled) first. Raw, they are digested very badly and can bring on all sorts of trouble with the intestines.

VITAMINS

A great deal has been written about the vitamin requirements of cats. Here are only the points on which cats differ from other animals — mainly from dogs, as their chief rivals for human friendship.

Vitamin A has to be present in the diet, because cats, unlike other mammals, cannot convert carotene (the precursor of vitamin A) into active vitamin A. The sources are fish, fish oil, liver, synthetic preparations.

Vitamin D. The classic signs of rickets brought on by a shortage of vitamin D are extremely rare in cats. They occur in kittens whose mothers were kept in dark rooms on rations poor in calcium, phosphorus and vitamin D. High doses of vitamin D must be avoided: hypervitaminosis is far more dangerous than a shortage.

Vitamin E. As was noted above, a shortage of this vitamin leads to steatitis, particularly on diets high in fat — the polyunsaturated fatty acids are to blame. This applies to the fat of sea fish above all. The daily dose recommended for prevention is 30 mg of vitamin E. The sources are cereal germ and vegetable oils; synthetic preparations.

Vitamin B1 (thiamine) — cats need five times as much of it as dogs! It is best not to feed cats raw fish, which contains the enzyme thiaminase, and that enzyme destroys this important vitamin. The treacherous part is that the clinical picture of thiamine deficiency looks very much like poisoning, and can mislead even a specialist. If raw fish makes up more than 10% of the cat’s daily ration, the vitamin has to be given separately.

Vitamin B2 (riboflavin). A shortage of it brings on fatty degeneration of the liver, disorders of sexual function in toms, and hair loss around the ears.

Vitamin PP (nicotinic acid). A shortage of it, too, produces a condition that is hard to diagnose. It is worth noting that signs of a shortage of vitamins PP, B2 and B1 sometimes appear on rations with too high an energy level, because the animal then eats less food overall, and so takes in fewer vitamins with it.

Vitamin B6 (pyridoxine). A deficiency goes with loss of weight, anaemia (which does not respond to preparations of iron and copper) and damage to the kidneys.

Vitamin H (biotin). A shortage of it leads to dermatitis of various kinds, abnormalities in the growth of the coat, and bloody diarrhoea.

MINERALS

In this group, too, there are a number of substantial differences from other mammals.

Ca:P (calcium: phosphorus). These minerals are given together on purpose, because their action is biologically linked and interdependent. A shortage of calcium, or an excess of phosphorus (which reduces the absorption of calcium), can lead in cats to nutritional secondary hyperparathyroidism — disorders of the musculoskeletal system, up to and including temporary and permanent paralysis, and the “washing out” of calcium from the bones of the pelvis and the spine. Put plainly: for every 1 g of calcium there should be 0.8 g of phosphorus, and any phosphorus above that will get in the way of calcium being absorbed. It is not enough, in other words, to give the right amount of calcium: the ration has to hold a strictly defined amount of phosphorus to go with it.

J (iodine). A deficiency can develop when there is too much meat in the ration, but it is practically never seen where sea fish or commercial foods are used.

Fe, Cu (iron and copper) are present in meat. Cats absorb them very well. A deficiency of these elements shows up extremely rarely.

Zn (zinc). Its absorption depends on iron and copper. A shortage brings disorders of vision, loss of colour in the coat, weakness.

Mn (manganese). No deficiency has been described in cats. An excess reduces fertility.