Pregnancy and nursing are not only responsible for many changes in a dog's body, but for changes in her lifestyle as well. If your dog is pregnant or nursing, pay special attention to her changing nutritional needs as she carries, delivers and nurses her puppies.
If you're planning to breed your female dog, it’s important to assess her body condition well in advance of breeding. Because of the physical demands of pregnancy and nursing, a dog with less-than-ideal health can experience problems:
Be sure to feed the proper amounts of a complete and balanced diet. This will support the mother's healthy weight and body condition before breeding and help maintain her health and that of her babies throughout pregnancy and lactation.
The gestation period for dogs is nine weeks. Pregnant dogs gain weight only slightly until about the sixth week, and then gain weight rapidly.
The energy requirements of pregnant dogs are reflected in the pattern of weight gain. Pregnant dogs will need to consume 25% to 50% more than their normal food intake by the end of pregnancy, but energy requirements do not increase until about the sixth week.
The best diet for pregnant and nursing dogs is a high-quality, nutrient-dense pet food formulated for all life stages or for growth. Although puppy diets are generally recommended for pregnant or nursing dogs, large-breed puppy formulas may not be appropriate for this use due to their adjusted energy and mineral content.
Pregnant dogs lose weight after giving birth, but their nutritional needs increase dramatically. Depending on litter size, nursing dogs might need two to three times their normal food requirement to nourish their pups. Be sure your nursing mom has plenty of water so she can generate the milk volume she needs to feed the litter.
To help your nursing dog get enough nutrition, you can try several tactics:

By four to five weeks after birth, most puppies are showing an interest in their mother’s food. Gradually, the puppies will begin eating more solid food and nursing less. At the same time, the nursing mother will usually begin eating less. Most puppies are completely weaned around age 7 to 8 weeks. By this time, the mother's energy requirement is back to normal, and she should be eating her normal pre-pregnancy diet.
Ethoxyquin is a synthetic antioxidant (artificially manufactured from other elements) that is approved for different uses.
Ethoxyquin is approved and regulated by the Food and Drug Administration (FDA) and the Association of American Feed Control Officials (AAFCO) for use as a preservative in animal feeds.
Dog-food manufacturers have been using ethoxyquin to prevent rancidity and to maintain the nutritional quality of their products for more than 35 years.
Ethoxyquin remains stable at the high temperatures required to process dog foods during extrusion. It is important in protecting fats and oils from degrading, losing available calories, and becoming rancid.
Despite the fact that all studies conducted to date prove that ethoxyquin is safe for use in all animal foods when used at approved levels, rumors continue to circulate to the contrary.
Individuals who seek to discredit the use of ethoxyquin will often cite certain studies that showed toxic effects in animals fed ethoxyquin. What these individuals fail to point out is that the animals in these studies were given excessive amounts of ethoxyquin—20 to more than 50 times the maximum limit—before negative effects were exhibited.