Digestion and utilization of straw. 2. Effect of different supplements on the digestion ammonia-treated straw

Abstract

ABSTRACTFour experiments with sheep fitted with rumen cannulae were conducted to investigate whether the rate of digestion of ammonia-treated straw, estimated as disappearance of dry matter from nylon bags in the rumen, might be increased by supplements of either soya bean meal, sucrose or sugar beet pulp at a level of 0·1, or by increasing the concentrations of dietary soluble micro and macro minerals.There were no differences among treatments in rate and extent of digestion of straw due to supplementations.In another experiment, the effect of increasing the proportion of molassed sugar beet pulp or rolled barley on rate of digestion of ammonia-treated straw was investigated. A greater proportion of sugar beet pulp (0·45) could be included in the diet before the rate of digestion was decreased in comparison with rolled barley (0·35).Assuming that the digestibility of the sugar beet pulp and the rolled barley was not changed by the increasing proportion in the diet, it could be calculated that the digestibility of straw was reduced from 0·538 with straw alone to 0·403 with the sugar beet pulp and to 0·218 with the rolled barley supplement when the supplements were included at a level of 0·70.