Good quality pet foods have been tested in animals to make sure the diet is adequate. If a food is meant for a particular stage of life, for instance growth of young animals, or if it is adequate for all stages of life, the bag label will say so. The initials AAFCO (Association of American Feed Control Officials) will appear with the statement.

What are the ingredients in the food?

The ingredients of commercial animal diets must be listed on the container label, but the quantities of each ingredient are not specified. However, the ingredients are listed in order according to the amount of each in the food. For instance, grocery store cat foods list ground yellow corn as the first and therefore major ingredient.

Ferret diets should list meat, poultry or fish meal, or animal by-products as the first ingredient. Look for a label that also lists other animal products, such as liver meal, eggs, or blood meal.

Sometimes manufacturers list several different kinds of grain right after meat or poultry meal. The total amount of grain might exceed the amount of poultry meal in the diet.

Typical ingredients in a good ferret diet

A typical ingredient list on a bag of good quality ferret food may appear as follows:

Chicken by-products, herring meal, corn, cod fish, animal liver, dried beet pulp, brewer's dried yeast, cane molasses, salt, sodium propionate, DL-methionine, L-lysine, taurine, vitamin A, vitamin D3 supplement, vitamin E supplement, riboflavin supplement, niacin, biotin, choline chloride, folic acid, thiamine mononitrate, pyridoxine hydrochloride, BHA, vitamin B12 supplement, menadione sodium bisulfite complex (a source of vitamin K), D calcium pantothenate, manganese oxide, inositol, ascorbic acid, iron sulfate, copper sulfate, zinc oxide, cobalt carbonate, potassium iodide, sodium selenite.

What nutrients are in the food?

The guaranteed analysis lists the percentages of crude protein, crude fat, fiber, ash, and moisture.

Crude protein is the total amount of protein in the food, but it says nothing about its digestibility. The quality of the protein is very important. Tendons and plant seeds contain protein, but ferrets cannot digest them.

To get an idea of protein quality, compare the guaranteed analysis to the ingredients list. If most of the protein is from poultry or meat meal, about 80% of it will be digestible. Protein from ground yellow corn is much less digestible. The label on some premium quality foods will tell you the digestibility of the protein. So will the price of the food – good quality protein is expensive. The lower the price, the more likely it is that the crude protein is of poor quality and low digestibility. Ferret diets should contain over 30% crude protein, of high digestibility.

Crude fat includes all the fat in the diet, from both plant and animal sources. Not all types of fat are equally digestible. Ferrets need animal source fats, and prefer the flavor of animal fats. Some generic cat foods are very palatable to ferrets because they are sprayed with animal fat after the pellet is formed. Generic cat foods contain 8 to 10% fat, not nearly enough for a ferret diet, which should contain at least 15% fat. If a generic cat food is the ferret's only source of fat, he will have a poor coat and dry, itchy skin.

Diets containing 30 to 40% fat are suitable for growing and lactating ferrets, but pets will become obese on palatable high fat foods. If extra fat is added to an otherwise poor quality diet, the ferret will eat enough to get the calories he needs, but may not get sufficient protein to maintain his body condition and health. Complete ferret diets and premium cat foods contain the correct balance of good quality animal fat and protein for your pet.

Fiber is undigestible carbohydrate that adds bulk to the diet. Sources of fiber include plant hulls, such as oat bran, or vegetable material such as beet pulp. There should be 4% or less fiber in foods intended for ferrets.

Ash is the mineral left if the food is completely burned. It is an indicator of the level of mineral available to the animal that eats the food. It should be less than 7% in a ferret diet. Excessive ash in the diet was once believed to be the most important factor in the production of bladder stones, but it is now known that there are several factors involved, and ash is not the most critical.

Pelleted and canned diets

Most dry cat foods contain about 10% moisture and 90% dry matter. The dry matter contains all of the protein, fat, and other nutrients – the rest is water. There are usually over 1800 calories per pound of premium quality cat food. An adult pet ferret requires about 200 calories per pound of body weight daily.

Canned cat food can be of very good quality and is usually more digestible than dry food, but the ferret's intestine has a very small capacity. Over 70% of canned food is water, and less than 30% is the dry matter that contains all the nutrients. Ferrets can't eat enough canned cat food to take in the calories they need. This is especially true for pregnant jills, when a lot of the space in the abdomen is occupied by the unborn kits and there is little room left for bulky food. Canned foods may tempt a ferret to eat when it has been sick, or can supplement the regular diet.