Dehydrated Alfalfa in Dairy Cow Diets

The objective of Experiment 1 was to determine protein degradation in the rumen and amino acid supply to and absorption of amino acids from the intestine of lactating dairy cows receiving supplements of soybean meal or a combination of dehydrated alfalfa and corn gluten meal. Four lactating Holstein cows, fitted with ruminal, duodenal, and ileal cannulae, were used in a switchback experiment. Two diets consisting of 50% corn silage and 50% concentrate were fed. One diet contained soybean meal and the other contained a mixture of dehydrated alfalfa and corn gluten meal. It was estimated that 76% of the dietary protein was degraded in the rumen with the soybean meal diet compared with 62% with the dehydrated alfalfa:gluten meal diet. Flow of total amino acids to the duodenum was 13% higher for the dehydrated alfalfa:gluten meal than for the soybean meal diet.