Performance of Lactating Cows Fed Alfalfa Hays Graded by Relative Feed Value System

Abstract

The objective was to determine if the relative feed value system of grading alfalfa hays could predict relative performance of lactating cows. In two feeding trials, 32 Holstein cows in a 4 4 Latin square arrangement were fed rations containing four lots of hay. All hays were chopped and fed as part of a complete ration once daily. In the first trial, two lots of a number 2 and a number 3 quality hay by relative feed value were fed as 30% of the dry matter of the rations. Measurements of production were not different among groups. In the second trial, cows were fed four rations containing hay of number 1, 2, 3, or 4 quality by relative feed value as 45% of the dry matter of the ration. Differences between groups were of milk production (30.2, 29.1, 29.0, and 27.6 kg/day), milk fat (2.96, 3.21, 3.09, and 3.17%), persistency (100, 98, 98, and 96%), and feed intake expressed as percent of body weight dry matter (3.4, 3.4, 3.4, and 3.1%).