Homemade pet food risks and how to do it safely

Most published recipes for homemade dog and cat food are not complete. When researchers at UC Davis analyzed 200 dog food recipes, 95% fell short on at least one essential nutrient, including recipes published in books by veterinarians. A homemade diet can be safe and balanced, but only when it is formulated for the individual animal and then followed exactly.

Why owners cook for their pets

The reasons are understandable. Owners want to know exactly what is in the bowl, and pet food recalls shake confidence in manufacturers. Some animals have medical needs that no commercial food meets well. In a survey of owners who had a recipe written for their dog by a hospital nutrition service, the most common motivation was a specific medical need. A dog with several confirmed food allergies, for example, may do best on a simple diet where every ingredient is known.

None of those reasons makes a recipe balanced. A freshly cooked meal can look wholesome and still lack calcium or vitamin D, and the effects of that shortfall build slowly.

What recipe studies have found

The dog study, published in the Journal of the American Veterinary Medical Association in 2013, took 200 recipes from 34 sources, including veterinary textbooks, pet care books and websites. Besides the 95% with at least one shortfall, more than 83% had several. Only 9 met AAFCO minimum standards for adult dogs. Choline, vitamin D, zinc and vitamin E were among the nutrients highlighted. Most recipes also gave vague or incomplete instructions, which leaves the cook guessing. The four recipes written by board-certified veterinary nutritionists were acceptable.

Cats fared no better. A 2019 analysis of 114 cat recipes from books and websites found that none met every National Research Council recommended allowance, even after the researchers made assumptions to fill gaps in the instructions. Nutrients most often short were choline, iron, thiamine, zinc, manganese, vitamin E and copper. Recipes written by non-veterinarians, and those without a supplement, did worse. In some of the better recipes, taurine adequacy could not be confirmed.

Nutrients that are easy to get wrong

Meat and a starch make a meal that looks complete. The Merck Veterinary Manual gives the example directly: a diet of mostly meat, or hamburger and rice, can cause calcium deficiency and secondary nutritional hyperparathyroidism, in which the body pulls calcium out of bone. Other points from the same reference:

• Calcium and phosphorus. Meat is rich in phosphorus and poor in calcium. Without a measured calcium source, the ratio is wrong from the start. Growing large-breed puppies are also harmed by too much calcium, so this is not something to fix by guesswork.
• Vitamin D. Dogs and cats make very little vitamin D in their skin, so they depend on their diet for it.
• Taurine, vitamin A and arachidonic acid for cats. Cats need all three from food. Taurine deficiency causes dilated cardiomyopathy and retinal degeneration, and plant ingredients contain no taurine.
• Zinc, iron and copper. Deficiencies show as poor growth, skin and coat changes, or anemia.
• Single-food excesses. Feeding mostly liver can cause vitamin A toxicity in dogs and cats. Raw egg white contains avidin, which binds biotin.

Deficiencies and imbalances can take months to show, and the early signs (a dull coat, weight change, low energy) are easy to put down to something else. That delay is why a recipe needs to be right before it is fed long-term, rather than adjusted after problems appear.

Raw homemade diets

A raw homemade diet carries the same nutritional risks plus a hygiene problem. When the FDA's Center for Veterinary Medicine tested pet foods for bacteria, raw products stood out. Of 196 commercial raw dog and cat food samples, 15 carried Salmonella and 32 carried Listeria monocytogenes. Of more than 800 dry, semi-moist and jerky-type samples in the same project, only one, a dry cat food, was positive. Raw meat bought for a homemade diet can carry the same bacteria.

The risk reaches the household. Bacteria spread from raw food to hands and kitchen surfaces, including the inside of the fridge, and from there to people. The FDA's advice for anyone who handles raw pet food:

• Wash hands with soap and water for at least 20 seconds after handling it or anything it touched
• Wash counters, bowls and utensils with hot soapy water, then disinfect them
• Keep raw pet food frozen until use and thaw it in the fridge or microwave, not on the counter
• Do not let the pet lick faces, especially right after a raw meal

The FDA also notes that thorough cooking to a proper internal temperature kills Salmonella and Listeria. For a homemade diet, cooking the meat removes most of this risk. Merck notes that raw and cooked forms of a food can differ in nutrient availability, so the nutritionist needs to know which will be fed.

Doing it safely

Get a recipe from a veterinary nutritionist

Board-certified veterinary nutritionists (diplomates of the American College of Veterinary Nutrition or the European College of Veterinary and Comparative Nutrition) complete residency training in animal nutrition. A review of commercial and homemade cat diets in the Journal of Feline Medicine and Surgery states that generic homemade recipes, such as those found online, are not recommended, and that homemade diets should be devised by a veterinary nutrition specialist. The same applies to dogs. A formulated recipe accounts for the animal's species, age, weight and health, and names exact ingredients, amounts and supplements.

Follow the recipe exactly

This is harder than it sounds. In a follow-up of owners who had recipes formulated for their dogs, only 4 of 30 with a complete diet history were feeding the recipe exactly as written. Most owners liked feeding home-cooked food and kept doing it, but many dogs later needed recipe changes. Swapping one meat for another, dropping a supplement because the dog dislikes it, or estimating instead of weighing all change the nutrient profile.

Use the supplements the recipe specifies

Nearly every balanced homemade recipe relies on added vitamins and minerals, usually including a calcium source. Human supplements are not interchangeable, because doses and forms differ and some contain ingredients unsafe for pets. Use the products named in the recipe, or ask the nutritionist before substituting.

Keep up follow-up visits

A recipe is written for the animal at one point in time. Weight changes, a new diagnosis or a move from growth to adulthood all mean the recipe needs review. Regular checks of weight, body condition and, where the vet advises, blood tests show whether the diet is working.

Toppers and mix-ins

For owners who want to add fresh food without taking on a full recipe, the lower-risk route is a complete commercial food as the base with small additions on top. Merck's guidance on treats applies here: because most treats and extras are not complete and balanced, they should make up less than 10% of daily calories. Cut the base food slightly to allow for them, or the pet will gain weight.

Suitable additions for most dogs include plain cooked lean meat without seasoning, cooked green beans or carrots, and plain canned pumpkin. Avoid onion, garlic, grapes, raisins and anything cooked with them. For cats, a little plain cooked chicken or fish works as a topper. A spoonful of something warm on top of the usual food is also a practical way to tempt a fussy eater, though a pet that suddenly stops eating needs a vet rather than a new topping.

The cost

Home cooking is often assumed to be cheaper. For a complete and balanced diet, it usually is not. When board-certified nutritionists costed six home-cooked recipes designed to match veterinary diets for dogs with chronic gut disease, the home-cooked diets cost more than dry commercial food, while the difference from canned food was not significant. Those figures cover ingredients and supplements only. The nutritionist's fee, follow-up visits and the time spent shopping, weighing and cooking come on top.

Sources

1. Homemade dog food recipes can be risky business, study finds. University of California, Davis, 2013.
2. Evaluation of the nutritional adequacy of recipes for home-prepared maintenance diets for cats. Journal of the American Veterinary Medical Association, 2019.
3. Nutritional Requirements of Small Animals. Merck Veterinary Manual.
4. Get the Facts! Raw Pet Food Diets can be Dangerous to You and Your Pet. U.S. Food and Drug Administration.
5. Commercial vs Homemade Cat Diets: What you need to know. Journal of Feline Medicine and Surgery, 2022.
6. Evaluation of owner experiences and adherence to home-cooked diet recipes for dogs. Journal of Small Animal Practice, 2016.
7. Feeding Practices in Small Animals. Merck Veterinary Manual.
8. Home-cooked diets cost more than commercially prepared dry kibble diets for dogs with chronic enteropathies. Journal of the American Veterinary Medical Association, 2022.