Effects of the supplementation of yeast, molasses and barley to barley straw diets on the intake, digestibility and ruminal fermentation in sheep

Abstract: The effects of the supplementation of yeast, molasses and barley to barley straw diets on the dry matter intake, digestibil-ity and ruminal fermentation in sheep were investigated. Ten male merino sheep were used in a changeover design trial of five 30-day periods. Baker’s yeast (50 g/kg straw), molasses (100g/kg straw) and barley grain (100 g/kg straw) were given either separately or in combination as supplements to barley straw. Supplementation increased the total dry matter intake by 18.2-36.8 %. Supplements given alone or in combination had no effect on dry matter and organic matter digestibility of the diet. Crude protein digestibility was decreased with molasses supplementation. Crude fiber digestibility was not affected by baker’s yeast supplementation but decreased with other supplements. The digestibility of nitrogen free extract was increased with carbohydrate supplementation. Rumen pH, total volatile fatty acids and ammonia-nitrogen values were not influenced significantly (p>0.05) by supplementation. As a conclusion, when urea to meet the requirements for rumen degradable N and vitamin-mineral premixes were mixed throughly with barley straw, usage of moderate levels of baker’s yeast, molasses, barley grain or the mixture of them increased total dry mat-ter and crude protein intake, but didn’t affect the digestibilities of dry matter and organic matter of diets and rumen parameters in sheep.