Abstract
Six successive trials with three adult rams (Sudan desert sheep) were conducted with the main object of finding a suitable index for the prediction of the nutritive value of protein in non-legumes for ruminants. The mean change in the concentration of ruminal ammonia, blood urea and ruminal V. F. A. 3 h after feeding legumes was considerably greater than after feeding the nonleguminous hays. Among the legumes berseem hay gave the least change in the concentration of ruminal ammonia, blood urea and V. E. A. The leguminous hays produced more gas under in vitro conditions than the non-legumes. Berseem hay produced the greatest volume of gas. Butterfly pea hay and lubia hay gave more or less similar results. Among the non-legumes the desert grasses gave the lowest values. Of all the feeds studied maize hay gave the highest nitrogen retention, followed by berseem hay. Despite this superiority of maize hay, the overall mean nitrogen retention of legumes was much greater than that of the non-legumes. Among the non-legumes dry desert grasses displayed a negative nitrogen balance. Regression equations based on the present data indicated that nitrogen retention only of leguminous hays could be always predicted from changes in blood urea concentrations. The present results also showed that the nitrogen retention of non-legumes and to a lesser extent that of all feeds taken together (i. e. legumes and non-legumes) can be assessed by using volume of gas produced in vitro (i. e. rate of in vitro fermentation).