日粮及粗料类型对奶牛产奶性能的影响

Impact of Diet and Forage Type on Dairy Cow's Lactation Performance

为探讨不同类型日粮和粗料对奶牛泌乳性能的影响,本试验选用12头健康荷斯坦牛为试验动物,随机分为3组,试验分两期进行。在精料相同条件下,第一期分别选用精粗比为40:60的秸秆型A日粮(粗料仅为干玉米秸秆)、40:60的青贮型B日粮和60:40的青贮型C日粮(B、C日粮粗料仅为玉米秸秆青贮)为不同类型试验日粮进行试验;第二期粗料分别以干玉米秸秆(a日粮)、青苜蓿干草(b日粮)、干玉米秸秆和青苜蓿干草混合(50:50,c日粮)为不同粗料类型试验日粮,进行奶牛饲喂试验。第一期试验结果表明:青贮玉米代替玉米秸秆或适当增加日粮中精料比例可显著提高奶牛的产奶性能,但乳脂率有降低的趋势。第二期试验结果表明:精料相同条件下,苜蓿青干草代替干玉米秸秆有助于提高产奶量和乳蛋白率,但是会显著降低乳脂率。玉米秸秆与苜蓿混合饲喂和单一饲喂玉米秸秆相比,产奶量与乳蛋白率均有所提高,但乳脂率显著降低;和单一饲喂苜蓿相比,虽然乳糖率略有提高,但产奶量和乳蛋白率明显减少,乳脂率也显著降低。

Diet and forage type has significant impact on dairy cow＇s lactation performance and organic health. To reveal the impact, 12 Holstein cow in good physical conditions were selected as the objects for 2-phase test, fed with stalk-type diet A （dry corn stalk as the forage） with concentrate-to-forage ratio of 40：60, silage-type diet B and diet C （corn silage as the forage） with concentrate-to-forage ratio of 40：60 and 60：40 respectively for one phase, and diet a, b, and c with corn stalk, alfalfa hay, and mix ture of corn stalk and alfalfa hay （at the ratio of 50：50） as the forage respectively provided with the same concentrate for the other phase. The test results of the first phase suggest that, either to replace corn stalks with corn silage or to increase the concentrate-to-forage ratio of a diet can significantly improve lactation performance of dairy cows, with tendency of lower milk fat content; and the test results of the second phase suggest that, provided with the same concentrate, to replace corn stalk with alfalfa hay contributes to higher lactation performance and lactoprotein content, as well as significantly lower milk fat content. By supplementation of alfalfa hay to corn stalk, both lactation performance and lactoprotein content increase, yet with significantly lower milk fat content; and by supplementation of corn stalk to alfalfa hay, despite of slightly increase in lactose rate, milk fat content shows significant fall as well as lactation performance and milk fat content.