Dogs are popularly thought to be carnivores and therefore able to subsist on diets composed entirely of meat. But such is not the case. Like most other animals, dogs are omnivores; they require a variety of foods -vegetables and grains as well as meats to meet their daily nutrient requirements.
As an omnivore, the dog must obtain energy from carbohydrates and fats to carry out life's activities. It also requires dietary proteins to furnish amino acids, which are the 'building blocks' of muscle, skin, hair, internal organs, blood, hormones, and enzymes.
Furthermore, dogs require dietary sources of minerals and vitamins, both to regulate many vital physiological reactions and to provide the necessary elements for the formation of bone and red blood cells.
The five groups of nutrients are discussed here. Most foods contain nutrients from more than one group. Only a few foods, such as sugars, pure starch, hydrogenated vegetable oils, lard, and other animal fats, provide a sole category of nutrient.
. Carbohydrates. Sugars and starches provide calories. Some, like fiber, aid greatly in maintaining normal intestinal functions, but do not contribute energy to the animal.
. Fats. These furnish a concentrated energy source and essential fatty acids. All fats contribute fatty acids to the diet, but only vegetable oils and chicken fat provide unsaturated and polyunsaturated fatty acids, the 'essential' ones.
. Proteins. These complex combinations of amino acids are essential for building and maintaining tissues and for certain biological functions. Meat, offal, and fish are high-quality (complete) proteins. Vegetables and grains are incomplete (low-quality) proteins. When combined correctly, however, they form complementary proteins: for example, oatmeal and rice, or rice and corn. Crude proteins also provide calories.
. Minerals. These are substances in the diet which cannot be oxidized any further. They are recorded as 'ash' on many pet food labels. Some, such as calcium and phosphorus, which comprise the major parts of bone, are required in relatively large amounts-about 1 per cent of the total dry weight of the diet.
Others, such as iron, a component of hemoglobin in red blood cells, are required in minute quantities-parts per million (p.p.m.).
. Vitamins. These are organic substances that promote normal metabolic functions- from the release of energy to the synthesis of normal vision. Dogs require the same vitamins as humans, except for vitamin C, which they make themselves.
. Water. Dogs cannot do without water. Humans, who often drink when they do not need to, sometimes forget that when animals want to drink it is because they are truly thirsty. A dog weighing about 30 kilograms (65 pounds) that is fed canned food drinks about a liter, or a quart, of water a day in warm weather.
Those given semi-moist or dry food may drink as much as 2 liters. Be sure to provide your dog with enough clean water, and if you take it for a long walk or out hunting, remember to give it water accordingly.