Pregnancy is stressful to the biology of a dog. Whilst a healthy male dog can father hundreds of puppies without any significant stress (except perhaps the problem of STD's), female dogs use a lot of energy and nutrient during pregnancy and lactation.

If a dog is not fed enough good quality food to supply these nutrients, she will have to use the ones stored in her own body's tissues. This will lead to malnourishment. And if she depletes her own body's sources of vitamins and minerals, a whole host of other problems will develop.

When a dog is pregnant, poor diet can express in the following ways:

1. An "out of condition" appearance of the dog. This may not be apparent until after the puppies are born. An actual loss in body weight throughout pregnancy can happen, but it's unusual in most instances.

2. Uncontrollable diarrhea after whelping (when the puppies are born), and throughout most of lactation. This is most often seen when she must increase her food intake too much to meet the increased demands of lactational because the food she has been eating is poorly digested or low in calories.

3. The "fading puppy" syndrome. The puppy may appear normal at birth, but several hours to days later it is found crying or whimpering, and chilled. It is off by itself, obviously disowned by the mother. Attempts to reunite the two are usually met with failure. The puppy's stomach will be empty and its body will be dehydrated. When weighed, it will weigh the same or less than the day before.

4. Anemias. When anemia occurs as the result of a dietary deficiency during pregnancy, it will be present in both the dam and pup. When both mother and pup are anemic, the first place to look for is the diet of the mother.

When the puppies are born, an inadequate diet during lactation is most likely to appear as:

1. Lactation failure (agalactia). This is a complete failure of the mammary glands. The dog produces no milk at all from which the pups can be nourished. These pups cry continuously, fail to gain weight, and unless immediate remedial feeding is started, the pups will die.

2. Lactation depression (dysgalactia). While the mammary glands are functional, they are unable to produce enough of milk to fully support the pups' complete nutritional needs. The pups' growth rate is restricted, and they may become stunted.

3. Deficient milk. The milk, although it may be produced in adequate amounts, is deficient in one or more nutrients.