不同精粗比日粮对奶牛产奶性能、乳品质和免疫力的影响

Effect of Different Ratios of Concentrate to Roughage on Milk Yield,Milk Quality and Immunity of Dairy Cows

旨在研究不同精粗比混合饲粮对奶牛产奶性能、乳品质和免疫力的影响,确定泌乳中期奶牛饲粮的适宜精粗比。本研究采用单因素完全随机区组设计,将45头产奶量相近的泌乳中期健康荷斯坦奶牛随机分成3组,Ⅰ组、Ⅱ组、Ⅲ组分别饲喂精饲料与粗饲料比例为40∶60、50∶50、60∶40的混合日粮,试验期为60d,通过测定各组平均日采食量、平均日产奶量、料奶比、乳脂率、乳蛋白率、乳糖率、乳干物质率、乳体细胞数、IgG含量、IgA含量、IgM含量等检测指标,比较分析不同精粗比饲粮对奶牛产奶性能、乳品质和免疫力的影响。结果显示Ⅱ组与Ⅰ组相比较,平均日产奶量、乳蛋白率、IgG含量、IgM含量均显著提高(P<0.05),体细胞数显著降低(P<0.05);Ⅲ组与Ⅰ组相比较,平均日采食、平均日产奶量、乳脂率、乳蛋白率、乳糖率、IgG含量、IgA含量、IgM含量均显著提高(P<0.05),料奶比、体细胞数显著降低(P<0.05);Ⅲ组与Ⅱ组相比较,平均日产奶量、IgG含量、IgA含量均显著提高(P<0.05),体细胞数显著降低(P<0.05)。表明饲喂不同精粗比饲料对泌乳中期荷斯坦奶牛的产奶性能、乳品质、免疫力的影响较大,日粮中精粗比为60∶40的饲喂效果最好,精粗比为50∶50次之,精粗比为40∶60最差。

In order to study the effects of different ratios of concentrate to roughage on milk yield,milk quality and immunity,determine the lactating cow diets suitable for coarse and fine ratio,this study adopted single factor randomized block design.45 healthy Holstein cows with similar milk yield and at mid-lactating period were randomly divided into 3groups（group Ⅰ,group Ⅱ,group Ⅲ）,and were fed diets with concentrate to roughage of 40∶60,50∶50,60∶40,the test period was 60 d.By measuring the average daily feed intake,average daily milk yield,milk feed ratio,milk fat percentage,milk protein percentage,lactose,milk dry matter ratio,and somatic cell count,IgG content,IgA content,IgM content and other indexes,the influence of different ratios of concentrate to roughage on milk yield,milk quality and immunity was analyzed.Results showed that average daily milk yield,milk protein content,IgG content,IgM content of both group Ⅱ and group I were all increased significantly（P〈0.05）,but somatic cell count decreased significantly（P〈0.05）;for groupⅢand groupⅠ,the average daily feed intake,average daily milk yield,milk fat percentage egg white,milk,lactose rate and IgG content,IgA content,IgM content all increased significantly（P〈0.05）,but the ratio of feed to milk and somatic cell count significantly dropped（PP〈0.05）;for group Ⅲ and group Ⅱ,the average daily milk yield,IgG content and IgA content were significantly increased（P〈0.05）,but somatic cells significantly decreased（P〈0.05）.It reveals that different ratios of concentrate to roughage affected the Holstein cows in mid-lactating period on milk yield,milk quality,immunity,among which the ratio of 60：40was the best,50：50next,and 40：60the worst.