Effects of barley silage particle size and concentration levels on feed intake, nutrient digestibility, rumen parameters in Kermani male sheep

To study the effects of barley silage particle size and concentration levels on feed intake, nutrient digestibility and ruminal parameters, four 14 months Kermani male lamb with an average weight of 35 ± 2 kg were used in change over design in 2×2 factorial arrangement with the four periods of 21 days. For the preparation of silage, 1200 kg of whole plant of barley was chopped with coarse and fine particle size and ensiled for 45 days in nylon bags. Experimental diets were: 1) 40% coarse barley silage and 60% concentrate, 2) 60% coarse barley silage and 40% concentrate 3) 40% fine barley silage and 60% concentrate and 4) 60% fine barley silage and 40% concentrate. Geometric mean of coarse and fine barley silage particle size were 13.95 and 10.83 mm, and pH was lower in fine barley silages (P=0.03). The results showed that DM feed intake was higher in 40% concentrate and diets (P<0.001), but the highest DM and OM digestibility were in 60% fine barley silage and 40% concentrate diet (p<0.05). Rumen pH value was higher in coarse silage diets four hours after feeding (p=0.005), but rumen ammonia nitrogen concentration was not affected by experimental diets. Microbial protein synthesis was the greatest in 60% fine barley silage and 40% concentrate diet (p<0.044). Reducing the level of concentrate and barley silage particles size, was caused the highest DM and OM digestibility, because of improved rumen conditions and increased surface area of silage particles.