The document discusses the objectives and nutritional needs of different types of mares in a breeding program. The objective is for high conception rates early in the season with few cycles per conception. An early conception allows the mare to exit the program sooner, which is more cost effective for the breeder. Pregnant mares have higher nutrient needs to support the growth of the fetus. Lactating mares also have increased needs to produce milk, ranging from 2-3% of their body weight daily, for the nursing foal.