Economic Relationships of Hay and Concentrate Consumption to Milk Production

Additional knowledge about the nature of the milk production function and its economic and nutritional implications are reported in this interdisciplinary study by economists, nutritionists, and statisticians. A milk production response surface was estimated from a basic experimental design that included four rations (including all hay) and three levels of feeding. While complementing in part the design of earlier Iowa studies, additional attention was given to important economic, biological, nutritional, and statistical considerations. Results obtained provide additional evidence indicating nonlinearity of the milk production function and decreasing marginal rates of substitution of grain for hay. Inferences concerning conditions of economic optima are similar to those obtained in the Iowa research. While primarily methodological in nature, this research indicates the need for large-scale experiments to increase the precision of estimated parameters. Designs providing for estimation of experimental movements in both horizontal and vertical directions on the milk-hay-grain surface are needed.