Energetics of Body Tissue Mobilization

Abstract

The dairy cow may rely heavily on body fat reserves as an energy source in early lactation. The extent to which milk may be produced from this energy source will be restricted by condition of the animal at the time of parturition. Data from this laboratory suggest that milk may be produced from body tissue reserves with an efficiency of 82 to 84% and that the body tissue reserves may be replenished in late lactation by deposition of body tissue with an efficiency equal to or exceeding that of milk production.It appears unrealistic to relate tissue energy changes to live weight change without some consideration being given to the change in rumen fill. If an estimate of change in rumen fill can be made, the caloric equivalent of empty body weight change may be assumed to be 5 to 7 Meal per kilogram live weight loss.