Use of the AADI system (amino acids truly digestible in the small intestine) in formulating rations for the dairy cow

Abstract

Appeared in 1992 for lysine and methionine, AADI system extended to the nine essential amino acids. In the current state from knowledge only five amino acidsare likely to be limiting (lysine, methionine, leucine,histidine and threonine). In practice, to improve the milk protein content it is necessary to optimize on two (lysine and methionine) or four (lysine, methionine,leucine, histidine) amino acids. To increase the production of milk, it seems preferable to optimize on histidine and threonine. These optimizations can be made by the use of raw materials suitable or by the use of amino acids correctly protected from degradations in the rumen. It would be desirable to establish response curves on a greater number of tests for leucine, histidine and threonine in order to be able to calculate as forlysine and methionine the interest economic to formulate on several amino acids.