To keep up with this nutrient demand, the sow must consume 2 to 4 times more nutrients than a non-lactating sow. The idea is to prevent or at least limit weight loss by the sow during lactation. Milk production also requires a considerable amount of calcium and other minerals. If it is necessary to cross-foster pigs it is best to do so within a day or two of farrowing. When cross fostering, avoid putting pigs of different sizes together.
Suffocation is the most common cause.
Crowding in the uterus during the late gestation can decrease pig size. As you might guess, the fewer pigs born in a litter, the larger the pigs. Pigs weigh about 2 to 3 lbs at birth. Energy stores in the newborn pig are low. If these stores become depleted and sufficient energy intake does not occur, hypoglycemia and hypothermia can result, coma and death.