My apologies. Yes, I’m starting off as such because despite my most sincere attempts to write the following in the most neutral and passive tone, I’m sure to offend or spark debate from someone -- such is the nature when discussing pet food!
To answer this question, here is a bit of background regarding pet food and dog and cat nutrition. Our understanding of animal nutrition has grown, and continues to grow, immensely. For example, deficiency of an amino acid, taurine, was found to be a leading cause of dilated cardiomyopathy (“DCM”), a type of heart disease, in cats. Appropriate supplementation in commercial cat foods has since made the disease largely a rarity in cats in the United States. (Remember, cats aren’t “little dogs,” and have specific dietary and other health needs!) In fact, there is an entire specialty in veterinary medicine devoted to nutrition, in which veterinarians can complete advanced residency training and certification.
As such, we know there are specific ranges of essential nutrients for dogs and cats (and such knowledge is certainly ever-evolving). Animal diets, whether commercial or freshly prepared, aim to meet these guidelines. Just as there are specific nutritional considerations for young children, growing puppies and kittens similarly have specific needs. For example, growing bones need specific levels of calcium, phosphorus, and vitamin D, particularly those animals that have a lot of growing to do, such as large breed puppies. Inappropriate levels of such nutrients can result in many ill-effects such as severely malformed bones. Organizations such as AAFCO provide guidelines on whether a purchased commercial diet meets the currently understood needs for growing animals (check out a bag of dog or cat food for the AAFCO statement).
So, to answer your question, we want to ensure that a growing puppy or kitten obtains these specific nutritional needs until they are mostly skeletally mature (i.e. their bones have largely stopped growing). This is generally around one year of age but may differ depending on the breed or animal, so always ask your veterinarian for specific instructions. On a similar note, ensure that young animals stay lean, as being overweight during development (and as adults!) has been implicated in many ill health effects.
For those looking to prepare food for their animals at home, especially growing puppies and kittens, make sure you obtain specific veterinary guidance prior to starting so that those growing bodies get exactly what they need to thrive!
Disclaimer: The content of The Bethel Grapevine’s Ask the Vet blog is for informational purposes only. It is not intended as medical advice and should not be treated as such. If you have a medical question about your pet, call or visit your veterinarian or a veterinary hospital.