Ever wondered why puppies and kittens need different formulas than adult dogs and cats? Have you been told your puppy’s breed will require an adult maintenance formula? Unsure when the best time is to switch your pet to an adult formula? If you’ve answered yes to any of the above, then please, dear reader, read on!

The first question is straightforward. Puppies and kittens develop rapidly over the first days, weeks, and months of their lives. They grow exponentially, meaning for a time they will gain more weight every day than they did the day before. All that growing means new bone, new muscle, and new connective tissues must be manufactured by their bodies, and all those new tissues rely directly on the nutrients fed to them. Remember, we quite literally are what we eat! Each new cell is made from precursors that come from the food in their bowl. You’re growing your puppy or kitten with each meal you feed them. This rapid growth period represents a time where they are extremely sensitive to the balance of nutrients they ingest. 

This is most dramatic and evident with respect to skeletal development and bone growth. For example, in pet nutrition we talk about a ratio of calcium to phosphorus that a formula can provide. For adult dogs and cats, this ratio is quite wide, ranging from 1:1 (i.e.: one-part calcium for every part phosphorus) to 2:1 (i.e.: two parts calcium for every part phosphorus). However, for puppies and kittens this range is narrower. Even if calcium and phosphorus are present in the formula exceeding the minimum requirements, an imbalance of too much or too little calcium to phosphorus can result in unhealthy changes to sensitive growing bones. At best, this can slow growth, but at worst it can result in fractures and deformities. Minerals aren’t the only nutrients that have different requirements between the stages of growth and adult maintenance, these also exist for protein and amino acids, fatty acids, and vitamins. For this reason, puppy and kitten growth formulas are recommended to support healthy development, as they are formulated specifically to meet the strict nutritional requirements of rapidly growing young bodies.

The second question comes from something I’ve heard many times from well-intentioned puppy parents. It usually involves large-breed dogs and some owners have been told to use an adult maintenance formula to prevent the puppy from growing too quickly. Sadly, this is not only ineffective, but can also lead to harm, as discussed above. The premise behind this common recommendation is often based on energy restriction – it is suggested that an adult formula will be less calorically dense, that is, will have less energy per kibble or mouthful, than a puppy formula. However, this is neither a guarantee (there are many high energy adult formulas) nor would it be an appropriate strategy, even if this were this true. The strategy is inappropriate because the growing puppy requires a certain amount of energy on a daily basis, regardless of how energy dense or diluted their food is. If the food is very light in calories, they need to eat more of it to meet their requirements. Restricting energy in a growing animal is not recommended as it can lead to a restriction of essential nutrients and result in growth disorders. For this reason, it is not recommended to try to implement a weight-loss program if a puppy or kitten is overweight. Better to wait until they are mature and then restrict their caloric intake. 

To determine how many calories your growing puppy or kitten should eat, check with your veterinarian. During your vaccination and checkup appointments, discuss your puppy or kitten’s growth and how their energy requirement will change over time. A great way to track their growth is growth charts. Using growth charts, you can make sure your puppy isn’t suddenly gaining weight or isn’t lagging behind. Both issues indicate a potential problem with their nutrition. Particularly for large breed puppies, keeping a slow and stable weight gain is important to allow their bones to develop well enough to handle their growing frame.

Lastly, it can be challenging to know when to determine the right time to transition from a development (puppy/kitten) formula to a maintenance (adult) formula. A number of factors including the predicted mature weight, age of skeletal maturity, and any underlying conditions, should be considered. Most puppies reach skeletal maturity between 10 and 11 months of age. Some, particularly large breeds, may still be growing and have unclosed growth plates in their long bones, requiring a puppy formula for longer. Using growth charts can help predict the age at which growth finishes, with the cessation of growing that is associated with the closure of bone growth plates and skeletal maturity.

Cats are different. Most cats typically attain their mature body size, in terms of length and height, before reaching the age of one. Their growth plates, however, may actually take longer to close. A kitten formula is recommended for at least a year, but better still to feed them the kitten food for up to up to 20 months. 

Adding a new furry friend to your family is always fun, so make sure you feed them for their best health and feed them a formula designed for growth during their more critical formative time. Setting them up for success starts at the beginning, and it starts with what they eat. As always, your family veterinarian is your best resource to recommend which type of formula is best for your particular puppy or kitten, as no two are the same.

Best wishes and tail wags,

Dr. Sarah Dodd

Here are some Halo formulas made specifically for the needs of growing puppies and kittens: