Investigation of Dietary Factors in Purified Diets for Ruminants

Abstract
The effect of supplements of vitamins other than A and D, 5% alfalfa and substitution of urea for casein in a purified diet developed for lambs was investigated. The complete diet contained casein, all the known vitamins, starch, glucose, fat, minerals and bicarbonates of sodium and potassium. Deletion of the vitamins other than A and D resulted in reduced gains. Addition of alfalfa had little or no effect on gains of lambs receiving casein diets. In the diets where urea was substituted for casein, alfalfa had a significant positive effect on gains of lambs. Samples of rumen fluid from lambs fed the urea-substituted diet without alfalfa had a significantly higher percentage of propionate and lower percentage of butyrate than the samples of rumen fluid taken from lambs fed the urea-alfalfa diet.