Computer Program for Maximizing Income above Feed Cost from Dairy Cattle

This paper extends computerized leastcost feed formulation for dairy cattle to the next logical step of profit maximization. The linear programming model presented simultaneously selects the concentrate and roughage components of the ration, the roughage-concentrate ratio, level of feeding per cow, and quantity of milk production maximizing income above feed costs. The nutritional and economic aspects of the model are presented in mathematical form, followed by two illustrations. Nutritional specifications include body maintenance requirements and the milk production response curve associated with alternative levels of energy and protein fed, a maximum voluntary feed intake relationship, calcium, phosphorus, and crude fiber requirements, and palatability restrictions on individual feeds. Economic specifications include prices and availabilities of feeds, and the prices and contract terms of milk sales. Nutritional relationships form the most critical portions of the model. In particular, the model can be improved over time by research designed to define more precisely the milk production response relationships for cows of different ability, size, breed, stage of lactation, and other important determinants.