Computer Simulation of Feed Costs for Milk Production in Relation to Dietary Ingredient Prices

Abstract

Feed costs were determined using linear programming techniques to produce least cost dairy diets. Effects of alfalfa hay and corn silage price and maturity of alfalfa hay on daily diet costs were determined. The influence of soybean meal price on the effects of alfalfa hay and corn silage price was also included. Regression equations were generated defining the responses in diet costs to changes in prices of these feeds and to maturity of alfalfa hay. Increasing alfalfa hay price from $40 to $120/909 kg increased feed cost per cow daily less ($.34) with low priced soybean meal (120/909 kg) than with high priced soybean meal ($.77). As corn silage price increased from $12.60 to $32.20/909 kg, daily feed cost per cow increased between $.81 and .96 daily with various price combinations for alfalfa hay and soybean meal. The response in diet cost to increasing the price of corn silage was affected little by alfalfa hay or soybean meal price. Increasing alfalfa hay maturity from immature to mature increased the cost of all diets. However, the effect of maturity on diet costs was greater with higher priced corn silage and with higher priced soybean meal. Advancing maturity increased diet cost more with $40 hay than with $120 hay. These results emphasize the importance of early harvest of alfalfa hay as one of the major factors in reducing the feed cost for producing milk. © 1989, American Dairy Science Association. All rights reserved.