Increases in energy intake decreased the concentration of total solids, protein, fat and gross energy of mare’s milk. Energy intake had a greater influence on the mare’s body condition than on milk energy production. It was concluded the objective of a feeding program for a lactating mare should be to keep the mare in a desirable body condition rather than to influence milk composition or production.

The National Research Council’s (1978) estimates of the energy requirements for lactation are based primarily on theoretical calculations. Some experiments have evaluated the accuracy of these recommendations (Jordan 1979; Sutton 1977), but in these studies not only was the digestible energy adjusted to different levels, but all of the other nutrients as well.