青贮牧草或青贮玉米饲喂羯羊时的随意采食量和瘤胃内纤维消化(英文)

Voluntary Intake and Ruminal Digestion of Fibrous Materials of Grass or Corn Silage by Wethers

用青贮牧草和青贮玉米饲喂羯羊,测定了青贮饲料随意采食量、瘤胃内纤维消化动态、对瘤胃微生物氮源和能源供应等因素的影响.瘤胃内纤维质消化、粗蛋白质和有机物降解采用尼龙小包技术测定.所用的两种青贮饲料在营养成分和发酵品质上虽有很大差异,但是绵羊的随意采食量基本相同.从瘤胃内纤维物质消化动态角度看,青贮牧草的潜在消化率高于青贮玉米,而青贮玉米潜在可消化纤维的消化速度快于青贮牧草,但两种牧草在绝对消化速度(潜在消化率与其消化速度之积)上没有差异,而且两者的瘤胃通过速度也基本相同.无论是哪种青贮饲料,其粗蛋白和有机物在瘤胃内降解率都很高,但两者间差异很小.两种青贮饲料的瘤胃降解氮、对瘤胃微生物氮源和能源供应等数值尽管较高,但是瘤胃氨态氮浓度也很高.这些结果表明,在青贮饲料随意采食量的调控上,瘤胃容积等物理因素也许起着重要的作用.

The experiment was conducted to study the relationship between voluntary intake of silages,ruminal fiber digestion and supply of nitrogen (N) and energy sources to the microbes in the rumen of wethers fed grass (GS) or corn silage <CS). Fiber digestion ,and degradation of crude protein and organic matter were determined by in sacco technique. The GS was much different from the CS in chemical composition and fermentation cllaracteristics. Wethers consumed similar dry matter from each silage. The potential extent of digestion (PED) of fiber in the rumen was higher for GS while digestion rate of PED (kd) was higher for CS.However,the product of PED and kd for both silages was not different. The rate of ruminal passage of digesta was also similar for both silages. Crude protein and organic matter of silages were highly degraded,and there was little difference between GS and CS. The degradable N,and the supply of N and energy to ruminal microbes showed high values , but this was associated with a pronounced peak of rumen ammonia-N concentration. It appears that the physical factors play an important role in regulation of silage intake through the digestion of fibrous materials in the rumen.