What a Dog Needs
Dogs require proteins, fats, vitamins, minerals, and water. While they have no absolute need for carbohydrates, they can burn them for energy. Carbs are included in dry foods to create the correct consistency for forming them into shapes; plus, they help maintain good gastrointestinal tract health.
Proteins and Fats
Proteins are actually composed of amino acids. There are twenty-two amino acids, ten of which must be provided in the dog's daily diet. It's not enough to just provide protein — it has to be the correct protein or blend of proteins. Dog foods that have passed the Association of American Feed Control Officials (AAFCO) feeding trials will have the correct amino acids included.
A certain amount of fat is necessary to make food palatable and to allow fat-soluble vitamins to be absorbed. Fat is also a high-calorie dietary component of great concern in the feeding of Yorkshire terriers, with their predisposition to pancreatitis. Do not buy a high-performance food for your Yorkie, as these generally have higher levels of fat than are necessary or even safe for a Yorkshire terrier.
Canines are scientifically classed as carnivores, but they are more properly called “opportunistic scavengers.” While wild canines certainly bring down big game such as moose, they also hunt mice, scavenge garbage dumps, and steal from other predators. They also eat ripe fruit and berries along with meat.
Vitamins and Minerals
Vitamins can be divided into two categories: fat soluble and water soluble. The water-soluble vitamins can't be stored in the body and must be consumed every day. Vitamin C and the B complex vitamins are all water soluble.
Many home-prepared diets fail when it comes to providing all the minerals dogs need. This can lead to a large variety of health problems. On the other hand, supplementing balanced diets with extra calcium or other minerals can also result in health problems.
Minerals also fall into two categories: macrominerals and trace minerals. Trace minerals, or microminerals, are needed in only very small amounts and can become toxic if provided at larger levels. Minerals interact with each other in myriad ways, and an excess of one can lead to a deficiency of another. Fresh, cool water should always be available to the dog as well — this will help the dog process these minerals.