There is some fascinating research going on the shows how critical nutrition is to the health of a dog or cat.
We are gaining new insight into the nutritional needs of pets every year. Research into the nutritional needs of young animals is especially interesting.
Newborn puppies and kittens lack certain pancreatic enzymes and intestinal enzymes that are part of the digestive process in adult pets. The muscle layer of the small intestine is also about 50% thinner. Puppies and kittens are specialized to digest lactose (milk sugar). They cannot digest table sugar (sucrose) or maltose in a homemade milk replacement formula. In addition, the mother's first milk, or colostrum, is rich in protein, immunoglobulins (antibiotics against disease), hormones and other substances which promote development of ht GI tract. Without getting colostrum from their mom, the intestinal mass does not double during the first 24 hours of life as it should, but instead grows much more slowly.
Young puppies and kittens should increase their body-weight by about 10% each day. If they can't get enough milk from the dam, they need a specialized milk replacer made for this purpose, as they cannot digest other types of nutrients. They need milk sugar, milk fat and milk protein.
From the third week to the seventh week of life there is a decrease in milk intake and three-fold in crease in solid food intake. By three weeks of dogeatage the intestinal wall thickness will double to facilitate the passage of solid food. The pancreas starts making digestive enzymes. The normal bacterial inhabitants of the intestinal tract begin to grow and establish themselves. In dogs, the amount of the different digestive enzymes will vary depending on the diet a puppy or dog is eating, because dogs are adaptable omnivores. Cats are predators and their enzyme balance is more fixed.
Dogs are unique species in that the adult body size of different breeds varies so much - from a two pound teacup poodle to a 200 pound mastiff. Small breed puppies may have two to three times the energy needs of larger puppies per pound of their body weight. In other words, big puppies need less energy per pound. Excessive amounts of calories in large breed puppies ca lead to early obesity or skeletal abnormalities.
Conversely, a study comparing the protein needs of miniature poodle puppies to Great Dan Puppies showed that the large Great Dane pups needed higher protein levels. The poodles had normal growth rates and normal blood chemistry values when fed a puppy diet containing 21% protein, but the Great Dane pups, though their growth rates were normal, had low serum albumin levels and red blood cell counts. So, small puppies need more energy density but less protein in their diet. food
Even more interesting is a study that showed Labrador retriever pups needed 50% more of the amino acid methionine than did the same age beagle pups. Proteins are made of amino acids. Not only do animals and humans need protein in our diets but we have requirements for certain specific amino acids too. It is interesting that two breeds of dogs in the same species can have very different protein needs. In the future, we may see pet foods manufactured to meet the special needs of particular breeds.
Because their growth rates are different, as well as their needs for energy density and protein in the diet, it is no longer recommended that owners feed the same puppy food regardless of the breed or size of their puppy. Larger breeds need a formula made to meet their requirements and to prevent bone and joint problems later on. Feeding adult dog or cat foods to puppies and kittens is also not appropriate.