Performance and income over feed costs when feeding alfalfa or grass hays and corn or wheat grains to high-producing dairy cows

Abstract

The objective of this study was to evaluate the production performance, nutrient digestibility, and income over feed cost (IOFC) of high-producing dairy cows consuming diets containing alfalfa or grass hays with either corn or wheat grain. Twenty-four Holstein cows were randomly assigned to 1 of 4 diets in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments (hay and grain types) and 21-d periods. Diets were formulated using a least-cost approach. To determine revenues from milk produced, the amount of ECM (kg·d −1 ) was multiplied by $0.303·kg −1 (i.e., class III milk price; US Federal Milk Marketing Order 5). The cost of the ration provided by the formulation software ($·cow −1 ·d −1 ) was divided by the predicted DMI (kg·cow −1 ·d −1 ) to obtain the cost of feed ($·kg −1 ), which was then multiplied by DMI (kg·cow −1 ·d −1 ) to provide the actual daily feed cost ($·cow −1 ·d −1 ). Cows consuming diets containing alfalfa hay consumed more DM than cows consuming diets with grass hay (27.1 vs. 24.4 kg·d −1 ). Cows consuming diets containing alfalfa hay produced more milk than cows consuming diets containing grass hay (47.5 vs. 44.7 kg·d −1 ). Milk from cows consuming diets containing grass hay had greater fat concentrations than milk from cows consuming diets containing alfalfa hay (4.22 vs. 3.89%). Using hay prices of $418 and $154∙t −1 , respectively, for alfalfa and grass hays, diets containing grass hay resulted in greater IOFC than diets containing alfalfa hay ($8.39·d −1 vs. $7.68·d −1 , respectively). Results of this study showed that IOFC can be supported when feeding grass hay using a least-cost ration formulation approach.