Complete and complementary feed for cats
18.06.2026 - Reading time: 3 minutes
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The market for cat food is vast. Various manufacturers offer different brands and varieties of wet and dry food, BARF, and even freshly cooked food. So what exactly constitutes complete feed and complementary feed?
What is the difference between complete feed and complementary feed?
A complete feed is a universal food product formulated to meet all nutritional requirements. Complete feed suitable for cats is available in dry, semi-moist, and wet forms, and nowadays also as BARF (Biologically Appropriate Raw Food) or fresh-cooked meals. It is crucial that the manufacturer adheres to FEDIAF guidelines regarding composition and assessment to ensure that all essential nutrients are present in adequate quantities. By following the manufacturer’s portioning instructions, feeding the appropriate amount of complete feed ensures the cat receives sufficient carbohydrates, proteins, fats, fiber, minerals (macro-minerals and trace elements), and vitamins.
Complementary feed for cats does not provide this comprehensive nutritional balance; depending on the recipe and intended use, specific components may be entirely absent or present in lower quantities. With complementary feeds added to a meal preparation, this may not always be immediately apparent, so pay close attention to the packaging label. The label must indicate whether the product is a complete feed or a complementary feed. However, complementary feeds usually come in a different form and are mixed into the main meal according to instructions. If you provide complementary feed in addition to the main meal, you should slightly reduce the portion of the complete feed (e.g., when giving cat treats). It is best to consult a feline nutrition expert beforehand and coordinate the ration with a veterinary nutritionist.
By the way: Cat grass is classified as a single feed ingredient. The grass fibers help bind hairballs—common in cats—and make them easier to regurgitate. Cat grass can be a valuable dietary supplement, especially for indoor cats that have no other way to ingest plant matter.
What exactly do the complementary feeds contain?
Complementary feeds are given in addition to a cat’s regular complete food when specific circumstances require extra nutrients to support their health. They can take the form of snacks and treats, or preparations designed to help address nutritional deficiencies. They can help prevent illness, alleviate ailments, and provide additional support for the cat’s body. Complementary feeds are available as treats, pastes, powders, gels, tablets, or drops that can be mixed into the food.
Additives in complementary feed include, for example:
- Vitamins are essential for life and are generally used only with homemade rations (such as BARF) and according to specific instructions. Excessive vitamin intake is possible, so you should not add them to the food on your own.
- Yeast or biotin for coat and skin problems
- Minerals (macro-minerals and trace elements)—such as calcium, magnesium, zinc, and iron—are essential for life and are generally used only with homemade rations (such as BARF) and according to specific instructions. Excessive mineral intake is possible, so you should not add them to the food on your own
- Fish oils (omega fatty acids) promote a healthy coatGreen-lipped mussel extract keeps joints and bones healthy
- Amino acids such as taurine are vital for supporting feline health
However, you should not use supplements on a hunch—especially for deficiencies caused by illness: Be sure to consult your veterinarian first!
How can I tell if my cat might be suffering from a deficiency?
Is your cat’s coat shaggy and dull—regardless of shedding seasons—are their eyes cloudy, and their digestion off? Does they seem generally listless and lethargic? All of these can be signs that your cat is coming down with an illness or has developed a nutritional deficiency. To be on the safe side, you should consult a veterinarian. If there is no underlying illness, appropriate supplements might help restore your cat’s vitality. However, be sure to discuss their use with your vet beforehand. Nutritional supplements are not a substitute for medication, and overdosing—or administering supplements that aren’t actually needed—can have a negative impact on your pet’s health.
