Comparison of Amino Acid and Alfalfa Supplementation of Purified Diets for Ruminants

Abstract

A series of experiments was undertaken comparing three purified diets for growth of lambs: the basal, diet 30, contained urea as the sole source of nitrogen; diet 27V2 consisted of the basal plus 5% alfalfa; and diet 28, the basal plus a selected group of amino acids based on the amino acid composition of alfalfa. As observed in previous studies, the alfalfa-supplemented diet was superior for growth to the basal urea diet. Results of this investigation also showed that the basal plus the amino acid supplement was equal to that of the alfalfa-containing diet for growth of lambs. The results from nitrogen balance studies indicated that neither the amino acid supplement nor the alfalfa improved the nitrogen balance, suggesting that the effect may have been mediated via changes through the microflora of the rumen. Gram stains from the samples of rumen fluid from the animals fed the experimental diets showed a marked difference in the flora of the animals fed the amino acid supplement.