籽粒苋青贮替代部分全株玉米青贮和精料对低产奶牛产奶量和乳成分的影响

Effect of partly replacing corn silage and concentrate with Amaranthus hypochondriacus L. silage on milk yield and composition of low-yield dairy cows

试验旨在研究籽粒苋青贮替代部分全株玉米青贮和精料对低产奶牛产奶量和乳成分的影响。采用随机分组试验设计,选取泌乳中期、体况相近、日产奶量15 kg左右的荷斯坦奶牛96头,随机分为3组,每组32头牛。对照组饲喂基础饲粮,试验Ⅰ组用籽粒苋青贮替代全株玉米青贮和精料的比例分别为38%和10%,试验Ⅱ组的替代比例分别为50%和33%。结果表明:试验Ⅰ组奶牛产奶量显著高于试验Ⅱ组和对照组(P<0.05);试验组乳蛋白、乳固体总量、乳脂肪和乳尿素氮均显著高于对照组(P<0.05)或有高于对照组的趋势;随试验时间延长,对照组乳脂肪和乳固体总量显著下降(P<0.05),而试验组无显著变化(P>0.05),3组乳蛋白和体细胞数均无显著变化(P>0.05),但乳尿素氮均显著提高(P<0.05)。研究表明,籽粒苋青贮适量替代部分全株玉米青贮及精料可以显著提高低产奶牛生产性能和牧场经济效益,不会对乳成分造成负面影响。

In order to investigate the effect of Amaranthus hypochondriacus L.silage replacing corn silage and concentrate on milk yield and composition of low yield dairy cows.A randomized trial design was adopted to select 96 Holstein cows with similar body conditions and a daily milk production of about 15 kg in the middle of lactation,and randomly divided into 3 groups,each with 32 cows.The control group was fed the basic diet,and the proportion of replacing corn silage and concentrate with Amaranthus hypochondriacus L.silage in the trial groupⅠwas 38%and 10%,and that in the trial groupⅡwas 50%and 33%.The results showed that the milk yield of the trial groupⅠwas significantly higher than that of the trial groupⅡand the control group(P<0.05).Milk protein,milk total solids,milk fat and milk urea nitrogen in the trial groups were higher than those in the control group significantly(P<0.05)or almost.With the extension of trial time,milk fat and milk total solids of the control group decreased significantly(P<0.05),while those of the trial groups had no significant changes(P>0.05).There were no significant changes in milk protein and SCC of three groups(P>0.05),but milk urea nitrogen of those increased significantly(P<0.05).It is concluded that partly replacing the corn silage and concentrate with Amaranthus hypochondriacus L.silage could significantly improve the performance of low-yield dairy cows and the economic benefits of dairy farm,which has no negative effect on the milk composition.