For the basics in dog nutrition please read the Canine Nutrition article we have posted.
For most of us it makes obvious sense that you need to feed a growing puppy differently from they way that you feed a full grown dog. Will a puppy survive and grow on adult dog food? Yes. Will it be healthy? No. There are three basic major differences between puppy foods and adult dog foods. There are also myriad minor differences that there is no point getting into as they would confuse things and make them unnecessarily complicated. Puppies need more protein that full grown dogs as they are growing a tremendous amount of muscle tissue during their development. They need more fat in their diet to fuel their growth rate and to lay down fat-based tissue like brain and nerve tissue. Thirdly they need a very different mineral balance in their diet to support the rapid growth of their bones.
Adult dog foods should contain between 20% and 24% protein. Puppy foods however should average around 26% to 28% protein. Again, the reason for this is the need in a puppy to provide the nutrition to create large amounts of new muscle tissue. The fat level in puppy foods should generally run in the 14% to 16% range, no higher! There is a great deal of tissue in the body that is fat-based, the most important one being the brain. Normal brain development and nerve development are very dependent on adequate dietary fat levels. Many organs also have a high requirement for fat during their development. Probably the most important balance in puppy food however is the balance between 2 minerals, Calcium and Phosphorous.
When bones are fully mature they require a very specific balance between their calcium and phosphorous levels to maintain good thickness (strength) and rigidity. Since Calcium and Phosphorous absorption in the bowel are inter-dependent this balance must be reflected in their ratio in the food. Adult dog foods generally have a Calcium:Phosphorous ratio very close to 1:1. However growing bones have a very different requirement for Calcium and Phosphorous as the “bricks” or basic molecular components of the bones are laid down. Puppy foods have a ratio somewhere between 1.2:1 and 1.4:1 of Calcium to Phosphorous. Bones of puppies that are fed adult foods are thinner and less able to support weight than those of puppies fed appropriate levels of these minerals. So it is vitally important that puppies, especially those of the larger breeds, are fed good quality puppy foods as they mature. Weak, thin, slow growing bones are a recipe for disaster in the large breed puppies.
How long do you keep puppies on puppy food? This is highly variable and depends very much on the expected adult size of the pup and their growth rate. As a general rule, very small breed dogs like chihuahuas would remain on puppy food until they are about 7 months old. Small breed dogs should remain on puppy food until they are about 8 months of age and medium breed dogs should remain on puppy foods for between 8 and 10 months of age. The very large breed puppies are often maintained on puppy food for at least a year, and sometimes even beyond that point. Once a puppy is full grown the high protein and fat levels in puppy foods tend to cause them to become rather chubby, so timing the switch to adult food is fairly important. Adult dogs should NEVER be maintained on puppy foods as they will develop severe bone and joint issues over time due to the abnormally high density of their bones. They will also generally be quite obese and often have kidney and pancreatic issues (see the article on Dog Nutrition). Our Vet clinic informs owners on their last “puppy” visit with us (at about 4 months of age) when we would advise the switch to adult food.
Large breed (and Giant breed) puppies are a special nutritional case when it comes to feeding puppy foods. NEVER FEED A GROWING LARGE OR GIANT BREED PUPPY ADULT DOG FOOD, EVER!!!! There are still people, and even breeders, who recommend this practice. It is the single worst way to feed a large breed puppy and can lead to a number of severe joint problems in adulthood. On adult dog foods the bones of these puppies mature at a very slow rate and they are very thin-walled due to the incorrect Calcium:Phosphorous ratio in the diet. This predisposes these puppies to arthritic problems as adults and makes it much more likely they will express serious arthritic disorders like hip and elbow dysplasia. These puppies need to be on what are commonly referred to as “Large Breed Puppy” foods.
The feeding requirements for all puppies were determined using studies involving medium breed dogs, beagles specifically. They are very active little dogs with rapid growth rates, but a limited amount of “mass” of growth compared to the larger breeds. Large breed puppies, by comparison put on a tremendous amount of tissue mass over their first year to 18 months of their lives. Feeding large breed puppies regular puppy food results in a very fat puppy during the most crucial phase of their joint and bone development. Carrying all of this extra weight on an immature frame creates the potential to cause damage to their immature joints resulting in severe arthritic conditions when these animals reach adulthood. “Large Breed Puppy” foods were developed specifically to address this problem. These foods have been specially formulated to contain the appropriate levels of nutrients to support rapid tissue and bone growth in these puppies, while preventing the massive tissue gain that regular puppy foods promote. Most importantly these puppy foods have the appropriate Calcium to Phosphorous balance that is key to developing strong healthy bones. These foods are also slightly lower in protein and fat levels (ie: energy levels) than normal puppy foods, which prevents these puppies from putting on excessive tissue mass during that extremely important 6 to 12 month growth phase.
It is very important that puppies are fed a food that is designed to meet their special needs as they grow. These needs vary depending on the expected size of the pup as an adult, and sometimes even by their breed. Remember folks, we as veterinarians are the very best source of this information that you have out there, and it is our job to see that you are properly informed and educated when you make these decisions!