Feed Processing. II. Effect of Feeding Expanded Grain and Finely Ground Hay on Milk Composition, Yield, and Rumen Metabolism

Open Access
Publisher Website
Google Scholar
Abstract
Six Holstein cows receiving an experimental ration of expanded sorghum grain (95-100% gelatinized) and alfalfa hay (finely ground) were compared in a 12-week trial with 6 Holstein cows fed a control ration of cracked sorghum grain and chopped hay (coarse). Enough grain and hay were fed at a 1 : 1 ratio to provide estimated net energy requirements. The experimental animals averaged 2.1 kg more milk (P < .01) and somewhat more protein and lactose (P < .10), but 1.8 kg less fat-corrected milk (P <.01) per day than the controls. Percentages of protein, lactose, ash, and solids-not-fat were similar for both groups. Due to reduction in milk fat percentage for the experimental group (2.2% compared with 3.8% for the controls), total solids were 10.9% compared with 12.6% for the controls. After the experimental group was fed the control ration 10 days, their milk fat percentage was similar to that of the controls. Feed protein was more efficiently converted into milk protein in the experimental group. Molar percentages of volatile fatty acids for the control and experimental groups, respectively, were: acetic, 68.1, 53.7; propionic, 17.4, 31.7; butryic, 12.3, 10.6; isovaleric, 1.2, 0.4; valeric, 1.1, 3.6. Rumen ammonia-nitrogen concentration was lowered considerably in the experimental animals. Rations fed had no effect on blood glucose level. Body weight gains were significantly higher on the experimental ration.

This publication has 18 references indexed in Scilit: