Corn and foxtail millet silages: effects of particle size and bacterial inoculation on intake, digestion, rumen Parameters, and feeding behavior in sheep

This study compared the effects of silage particle size (۸ vs. ۱۶ mm) and inoculation with lactic acid bacteria on the nutritional and physiological responses of sheep fed with diets containing corn or foxtail millet silage. Two separate experiments were conducted for ۹۰-day periods arranged as ۲×۲ factorial experiment within a randomized complete block design. While particle size and inoculation had no significant effect on dry matter (DM), crude protein, or neutral detergent fiber concentrations in corn silage, in millet silage DM content was significantly higher with long particles (۳۹۵ vs. ۳۵۰ g/kg DM; P<۰.۰۱). Silage pH was significantly affected by particle size in both corn (P<۰.۰۵) and millet (P<۰.۰۱), with short particles yielding lower pH. Bacterial inoculation further reduced pH only in millet silage (P<۰.۰۱). The DM and organic matter (OM) intake were greater with short-particle silages, but digestibility improved only in the sheep fed with short, inoculated millet silage diet (P<۰.۰۱). Ruminal pH remained unaffected by two factors in corn silage diets, but in millet silage diets, it was significantly lower at ۲ and ۴ h post-feeding with short silage particles size diets (P<۰.۰۱). Ruminal microbial nitrogen and protein synthesis were higher with short-particle corn silage (P<۰.۰۱), whereas millet silage showed a significant particle size×inoculation for these parameters. Chewing behavior also differed; sheep fed on short corn silage chewed longer (P<۰.۰۱), while in millet silage, feeding time increased with long particles silage diet and rumination time was longer with short particles (P<۰.۰۵). Overall, corn silage responses were driven mainly by physical form, whereas millet silage benefited from the combined optimization of chop length and microbial inoculation.

کلیدواژه ها:

bacterial inoculation ، physical characteristics of diet ، microbial protein ، silage particle size