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The protein nutrition of dairy cows has been studied extensively in terms of response to different levels and sources of crude protein in the diet but individual amino acid requirements for different stages of lactation have not been determined. The amino acid requirement is significantly affected by the rumen degradability of dietary crude protein. The differences in degradation of crude protein from forages and concentrates and the dynamics of microbial protein synthesis in the rumen have made it difficult to significantly after the ratio and the quality of amino acids reaching the small intestine. Previous studies support the hypothesis that the principal sources of variation in the amino acid balance of intestinal digesta are the amino acid composition of feed proteins and the proportional flow of ruminally undegraded intake protein and microbial protein to the intestines. Attempts to increase the passage of essential amino acids to the intestines by feeding protein sources with low rumen degradabilities had variable success.Recently it was found that there is increasing evidence that the addition of certain amino acids can improve milk production and particularly milk protein.

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Dr. Tarek Abdelfattah Mohamed Aly Morsy - Professor of dairy animal nutrition, National Research Centre, Cairo - Egypt. He has interest in the following research areas: Dairy Animals Nutrition, Feed Enhancements, Rumen Fermentation, Milk Quality and Healthy Dairy Products, Application of Biotechnology in Dairy Animal Nutrition.

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