利用体外消化率评价青贮品质的问题探讨

饲草青贮后会产生易挥发的发酵产物,在烘干时使干物质损失,从而低估了消化率。采用纤维素酶-胃蛋白酶两级离体消化法测定玉米(Zea mays L.)、羊草(Leymus chinensis Tzvel.)、苜蓿(Medicago sativa L.)的青贮料与其原料的消化率,并进行校正。结果表明:青贮饲料体外干物质消化率的实测值与校正值差异显著,校正后青贮饲料体外干物质体外消化率显著提高,相比之下,玉米青贮饲料提高的幅度更大,9月7日、9月17日收获的玉米分别提高了6.72%和5.63%。7月18日收获的羊草、9月7日收获的玉米、9月24日收获的苜蓿青贮饲料体外干物质消化率的实测值与原料相比均显著降低,但校正后都显著高于原料。8月19日收获的羊草和9月17日收获的玉米青贮饲料体外干物质消化率校正后虽比实测值显著提高,分别提高了2.00%和5.63%,但与原料相比还是显著下降,但降低幅度变小。7月18日收获的羊草和9月24日收获的苜蓿青贮饲料体外干物质校正消化率和原料差异不显著。

Discussion on Silage Quality Evaluation Using In Vitro Dry Matter Digestibility

The digestibility of silage could be underestimated due to fermentation product volatility.Digestibility of both silage and its crude materials such as corn(Zea mays L.),guineagrass(Leymus chinensis Tzvel.) and lucerne(Medicago sativa L.) using the pepsin-cellulase two-step in vitro technique was studied comparably here.Results indicated that there is significant deference between measured and adjusted IVDMD value of silage.Adjusted IVDMD values of silage are higher than measured ones.The adjusted IVDMD value of corn silage harvested in 7 Sep.and 17 Sep.increased 6.72% and 5.63% compared with measured ones,respectively.The measured IVDMD value of guineagrass silage harvested in 18 July,corn silage harvested in 7 Sep.and lucerne silage harvested in 24 Sep.decreased compared with that of crude materials.But the adjusted values of these silages all were higher than that of crude materials.Although the adjusted IVDMD value of guineagrass silage in 19 August and corn silage in 17 Sep.increased 2.00% and 5.63% compared with measured values,respectively,these values are still lower than that of crude materials.There is no significant deference between adjusted IVDMD value of guineagrass silage in 18 July as well as lucerne silage in 24 Sep.and that of their crude materials.