Utilization of Micronized Sorghum Grain by Dairy Calves

Abstract

Forty-two heifers (24 Holsteins and 18 Ayrshires) were used to compare utilization of rations containing 60% dry rolled and micronized sorghum grain. Calves within each breed were assigned to three groups: (a) control (dry rolled), (b) micronized (380 g/liter), and (c) micronized (230 g/liter). During an 8-wk trial, weights were recorded weekly and rumen samples for volatile fatty acid determination were taken 4 to 5h after feeding during the 4th wk. Nine bull calves (six Holsteins and three Ayrshires) were in a 3×3 Latin square design to determine digestibility of rations in the heifer trial. Mean weight gains were 46.9, 46.0, and 43.8kg for heifers fed dry rolled, micronized (380 g/liter), and micronized (230 g/liter) sorghum grain. Average feed intake was higher in the group of heifers fed the dry rolled grain ration, i.e., 164.7kg compared to 150.0 and 142.4kg for the above groups fed micronized grain. There was a trend for greater feed efficiency by calves fed micronized grain which was consistent with slightly higher digestibility of dry matter and organic matter in the micronized rations. Micronized sorghum grain was accepted readily by young dairy calves.