Effect of silage Physical processing and non-forage fiber levels on feed intake, nutrient digestibility, rumen parameters and feed intake behavior of sheep

In Iran, corn silage is an important part of ruminant forage. Mechanical processing of corn forage can improve the properties of corn silage. In this process, chopped fodder is processed using toothed rollers. In this way, it is increased the digestibility of starch and cell wall. Barley starch has a fast ruminal fermentation, and while increasing the production of microbial protein, it can cause an increase in the incidence of digestive abnormalities in ruminants. Neutral detergent fiber (NDF) of sugar beet pulp are very digestible. This study was conducted in order to investigate the effect of two processing levels of corn silage and barley grain and sugar beet pulp on silage quality, feed intake, digestibility of nutrients, rumen parameters and feed intake behavior of Kermani sheep.

In this research, four 2-year-old Kermani lambs with an average weight of 42 ± 2.8 kg were used in a 2x2 factorial experiment in the form of a Latin square design in four periods of 21 days. The experimental diets were: 1)processed corn silage + concentrate with barley seeds, 2)processed corn silage + concentrate with sugar beet pulp, 3)unprocessed corn silage + concentrate with barley seeds, 4)unprocessed corn silage + concentrate with sugar beet pulp. The daily feed was distributed in two equal portions on 8/00 and 18/00. Research data were stored in Excel software and statistically analyzed with SAS software.

Silage processing decreased the percentage of dry matter (DM) and NDF, increased NH3-N, pH (4.42 and 4.04, respectively, P=0.02) and sensory evaluation (15 and 18, respectively, P=0.02) score of silage. Feed intake was higher in the processed silage diets and the diet with barley grain. The digestibility of organic matter (OM) and NDF was higher in the diet containing sugar beet pulp. Ruminal NH3-N (mg/dL) (21.17 and 22.81, respectively, P=0.02) was higher in diets containing processed silage at two and eight hours after feeding, and it was lower in diets containing sugar beet pulp at 6 hours after feeding. The pH of the rumen fluid in the diet containing sugar beet pulp with processed silage was significantly higher than in other experimental diets at eight hours after feeding (P=0.01, 6.92),. The population of rumen protozoa was higher in the unprocessed silage and barley grain diets. Feed intake time was higher in unprocessed silage diets. However, the most rumination time was related to sheep fed processed silage diets. The highest chewing time was in barley seeds diets.

Although corn fodder processing caused a decrease in the sensory evaluation score in the processed silages, it caused an increase in DM intake and OM intake in diets containing this type of silage. The effect of processing silage on animal responses were greater than the effect of barley grain or sugar beet pulp on these responses. It is recommended to process corn fodder with dry matter of about 30 percent.