杂交狼尾草、羊草不同干草比例对奶牛生产性能和乳品质的影响

为研究饲粮中用闽牧6号杂交狼尾草(Pennisetum americanum×P.purpureumcv.Minmu 6)鲜草代替等量干物质羊草(Leymus chinensis)干草对奶牛生产性能及乳品质的影响,选用24头胎次一致(1胎)、产奶量相近(15kg左右)的荷斯坦奶牛,设置6个处理,各处理间饲粮中闽牧6号杂交狼尾草的重量分别为:0(CK)、7.50、15.00、22.50、30.00和37.50kg。试验期40d(预试期10d,正试期30d)。结果表明,1)夏季30~37℃条件下,在中低产奶牛饲粮中使用7.5~37.5kg杂交狼尾草鲜草替代羊草干草,各处理奶牛的干物质采食量和产奶量差异不显著(P0.05)。2)从试验前、后产奶量的对比来看,与全干草的对照组相比,给饲鲜草的试验组产奶量相对更稳定。3)饲粮中供给22.5kg杂交狼尾草鲜草时,每100g牛乳中α-亚麻酸含量最高为15.88mg,比CK增加了43.41%(P0.05)。由此可知,夏季高温条件下,在奶牛饲粮中供给杂交狼尾草鲜草有助于稳定产奶量,并提高部分试验组乳中α-亚麻酸含量。

Effects of different rations of hybrid Pennisetum americanum×P.purpureum cv.Minmu 6 in Leymus chinensis hay on production performance and milk quality of dairy cows

The effects of different rations of fresh hybrid P .americanum × P .purpureum cv.Minmu 6 in Ley-mus chinensis hay on production performance and milk quality of dairy cows were studied using a randomized block experiment with 24 Holstein dairy cows which were first birth with similar milk production(15 kg).The experiment had 6 different ratios of fresh Minmu 6 forage (CK,0;Group Ⅰ,7.50 kg;Group Ⅱ,15.00 kg;Group Ⅲ 22.50 kg;Group Ⅳ,30.00 kg;and Group Ⅴ,37.50 kg)with 4 cows in each group and had 40 days treatment period including 10 days for pre-trial period and 30 days for regular trial period.In summer around 30~37 ℃,there was no differences (P>0.05)between treatments fresh Minmu 6 forage for dry matter intake and milk production.The milk production of the experimental group with fresh forage was more stable than that of the control group.Theα-linolenic acid (ALA)content of milk in Group Ⅲ with 22.50 kg fresh Minmu 6 forage was 15.88 mg?100 g-1 which increased by 43.1% compared with CK (P<0.05).In conclusion,fresh Minmu 6 forage in hay was helpful to stable the milk production and can improve ALA content of milk.