ESTIMATES OF CREEP FEED REQUIREMENTS OF NURSING CALVES AND THE TOTAL ENERGY REQUIREMENTS OF BOTH COW AND CALF TO PRODUCE THE WEANED CALF

Metabolizable energy and net energy systems were used to calculate creep feed requirements of nursing beef calves. These methods allow estimation of cumulative energy requirements for creep feed of growing calves for any combination of birth weight, rate of weight gain, energy concentration of the diet and level of milk production of the dam. Creep feed requirements estimated by these methods are in reasonable agreement with experimental findings. As examples, the methods were used to calculate creep feed energy requirements and total energy requirements of cows and calves in two situations: (a) combinations of three levels of milk production and three cow sizes where calf growth rate is proportional to cow weight and (b) combination of three levels of milk production and calf growth rates where growth rates are assumed independent of cow size. In the latter situation, the extra energy required for a unit change in output increased with increased liveweight gain, but decreased with increased milk producti...