Volatile fatty acids in the ruemen of sheep fed grass, unwilted and wilted silage, and barn-dried hay

Abstract

SUMMARYExperiments were carried out to assess the effect of the following diets: unwilted and wilted silage, barn-dried hay and wilted silage and ensiled mixtures of grass and barley on the ruminal VFA patterns in sheep.There was a tendency for the unwilted silage to result in a slightly higher level of rumen acetate and a lower level of propionate than grass, wilted silage or barn-dried hay. In two of the experiments (Exps. 2 and 4) significant direct relationships were found between rumen acetate and the crude-fibre content of the diets and significant inverse relationships were found between the rumen propionate and the crude-fibre content of the diets.Significant relationships were also found between the rumen acids and the metabolizable energy content of the diets and in Exp. 2 there was a significant relationship between the rumen acetate and the water-soluble carbohydrate content of the diet.The addition of barley meal to grass produced different ruminal VFA patterns in sheep fed the ensiled material and the resulting silage.