What Causes a Puppy to Stop Growing?

By Sarah Wooten, DVM

Puppies that are not growing at a normal rate or who are too small for their age are stunted; that is, something has prevented them from growing naturally or at a normal rate.

There are several things that can cause stunted growth in puppies, ranging from intestinal worm infections to genetics. In this article, we will address the most common concerns associated with stunting, and whether or not these concerns actually cause stunted growth in dogs.

Does Worm Infection Cause Stunting?

The most common reason why a puppy’s growth becomes stunted is because they are infected with hookworms or roundworms. Intestinal worms are extremely common in puppies in the United States — they either contract worms from their mother or from the environment around them. If a puppy has an extremely heavy worm infestation, the worms can steal enough calories from the puppy to slow down her growth. Puppies that have a heavy worm burden typically look unthrifty: they have a poor haircoat, diarrhea, a big pot belly, and are small and thin despite a voracious appetite.

The good news is that once the puppy is free of worms, the body can heal itself and regain normal growth and development.

To prevent worms in your puppy, follow the deworming schedule set forth by your breeder and/or veterinarian. If the schedules differ, follow the worming schedule set forth by your veterinarian.

Does Malnutrition Cause Stunting?

A common question puppy parents ask is whether a puppy’s growth can be stunted by taking him off puppy food too soon. The short answer is no, you will not stunt your puppy’s growth by switching to adult food too soon or by mildly under-feeding. Puppy food is formulated to support normal growth and development, and, while it is not ideal, there are millions of dogs out there that do just fine on a diet that is formulated for all life stages, and which are fine to feed to a puppy.

On the contrary, you can do much more damage to your puppy’s long term joint health by over-feeding or giving supplements while the pup is still growing. According to the lifetime studies conducted by Purina on Labrador Retrievers, dogs will live on average two years longer and have much less chronic disease if you keep them slim their whole life. Ask your veterinarian about what the right body condition is for your puppy, and for tips on how much to feed to keep your puppy in his ideal condition.

Just like a human child, your puppy will go through growth spurts during the first year. There will be days when she may need to eat more than the amount she will need as an adult. My 75-pound Goldendoodle, for example, eats two cups a day of dry dog food, but when she was growing (about eight months of age) she would eat up to four cups of food a day. You will need to be flexible about the amount you are feeding her sometimes in order to support her growth and development.

Another common question is whether malnutrition itself will cause stunting. To be sure, puppies that suffer under extreme situations like starvation are at risk for stunted growth. But most puppies that are in caring, loving homes with pet parents who measure the appropriate amount they feed to their puppies — food that is adequate for supporting bones, muscles, and other tissues as they grow — will not have stunting from malnutrition, even if they keep the puppies slim.

Does Spaying or Neutering Cause Stunting?

Having your dog spayed or neutered early will not stunt your puppy’s growth, but it might affect the joints of large breed dogs. Studies show that early spay/neuter does affect the growth plate, delaying its closure and causing dogs to grow taller than they should have. This can predispose the dog to later joint problems. 

This is an excellent topic to discuss with your veterinarian. For small or medium sized dogs, the standard recommendation is still to spay/neuter the dogs between 6-8 months of age. For large breed dogs, however, the recommendation is to hold off until the dog is older to lower the risk of joint disease. For females, spaying should wait until after the first heat cycle, and for males, neutering can be scheduled when the dog is around two years old.

Ask your dog’s doctor for her or his recommendations on when to spay or neuter your dog, and ask them for their reasons behind their recommendations.

Does Strenuous Exercise Cause Stunting?

Engaging in strenuous exercise with your puppy will not stunt his growth, but the excessive impact associated with running may damage the growth plates of the long bones and cause them to develop abnormally, predisposing your puppy to joint issues later in life. Again, this is more a problem for large breed dogs because they simply weigh more.

Playing fetch and allowing your puppy the space to run around until she is tired is fine, but don’t take her jogging or running until she is done growing. For clients who want their medium or large breed dog to be their jogging partner, my standard recommendation is to wait until after 15 months to allow for the bones to grow properly.

Are Certain Breeds at Risk for Stunting?

Is there any one breed that is more predisposed to stunting than another? There is a rare disease called pituitary dwarfism in German Shepherds and in some Labrador Retrievers that has a genetic component, but these conditions are very rare and not generally seen in companion animals.