The effect of barley silage particle size and concentrate levels on physical characteristics, dietary intake and digestibility of diets, nitrogen retention, microbial protein synthesis and eating behaviors in Kermani sheep

In Iran, Barley silage is considered much lower than the other silages. Barley can provide perfect fodder for ruminants in early spring, when other forage are not available.
This experiment was conducted to determine the effects of barley silage particles size and levels of concentrate on feed intake, digestibility, nitrogen balance microbial protein Synthesis and eating, Rumination and chewing activity in Kermani sheep.
Material and The experiment was carried out in sheep farms of Department of Animal Science, Shahid Bahonar University of Kerman. Iranian conventional varieties of barley grain was grown in the farm of agricultural faculty in November 2011. About 1200 kg of barley fodder were harvested in green stems and doughy seeds condition, and chopped in sizes 24 and 12 mm and was ensiled in plastic bags without any additives. Silos were opened after 45 days and evaluate the physical properties and visual appraisal of barley silage. Experimental diets were: 1) 40 percent coarse barley silage and 60 percent concentrate 2) 60 percent coarse barley silage and 40 percent concentrate 3) 40 percent fine barley silage and 60 percent concentrate 4) 60 percent fine barley silage and 40 percent concentrate. Four mature male sheep weighing 52 ±4/0 were used in the experiment. Sheep were kept in metabolic cages and had free access to feed and fresh water and were assigned randomly to 2×2 factorial dietary treatments in a changeover design experiment. The experiment consisted of four periods, the experimental periods were 21 d each and included an adaptation period (d 1 to 14), a data collection period (d 15 to 20) and chewing behavior (d 21).
There was no significant difference in visual appraisal of silages, however pH was lower in fine barley silage (P=0.003). The pef, peNDF and geometric mean were higher in coarse barley silage diets. Dry matter intake was influenced by the levels of concentrate (p=0.02) and were higher on diets with 60% concentrate, but barley silage particles size had no effect on dry matter intake. NDF intake was influenced by the silage particles size and concentrate levels and was the lowest in the diet of 60% concentrate and fine barley silage particle size (p=0.05). Dry and organic matter digestibility were influence by barley silage particles size and concentrate levels, the highest dry and organic matter digestibility were in diet of fine silage particle size and 40% concentrate level (P The highest dry and organic matter digestibility were in 40 percent concentrate and fine barley silage diet, because contact with the rumen microorganism was increased with the silage particle size reduction.