围产前期饲粮粗蛋白质水平对荷斯坦经产奶牛产后生产性能和血液指标的影响

本试验旨在研究围产前期饲粮粗蛋白质水平对产后奶牛生产性能和血液生化指标影响。选取预产期、胎次、体重相近,上一个泌乳期时长、产奶量相近的21头经产荷斯坦奶牛,随机分为3组,每组7头。在围产前期(产前21 d内)饲喂粗蛋白质水平分别为12.12%(A组)、13.07%(B组)、14.02%(C组),产奶净能均为5.50 M J/kg的3种不同饲粮,研究其对奶牛产后1~30 d的生产性能和血液指标的影响。结果表明:1)产后1~30 d,B组的干物质采食量分别比A、C组高5.41%、5.85%(P0.05)。产后30 d,A、B和C组体重分别损失6.30%、5.03%、8.22%,C组体重损失最高。B组与其他2组相比,有增加产后产奶量的趋势,但各组间差异不显著(P0.05)。产后2~10 d,B组的乳糖率比C组高4.31%(P0.05)。围产前期B组的粗蛋白质表观消化率比A组高12.56%(P0.05)。2)产后10、20、30 d,B组血清葡萄糖(GLU)含量分别比C组高31.41%、29.47%、21.38%(P0.05)。分娩当天,B组血清总蛋白(TP)含量比C组高12.98%(P0.05)。产后30 d,B组血清白蛋白(ALB)、瘦素(LP)含量分别高于C组14.69%、5.97%(P0.01)。产后20 d,B组血清甘油三酯(TG)含量均比A、C组低3.57%(P0.05),血清胰岛素(Ins)含量分别比A、C组低7.26%、12.47%(P0.01)。产后30 d,B组血清胰岛素样生长因子Ⅰ(IGF-Ⅰ)含量比C组低4.94%(P0.01)。综上,饲粮粗蛋白质水平13.07%为围产前期适宜饲粮粗蛋白质水平。

Impact of Prepartal Dietary Crude Protein Level on Postpartal Production Performance and Blood Indexes of Multiparous Holstein Dairy Cows

The objective of this study was to determine the effects of perpartal dietary protein level on postpartal production performance and blood indexes of multiparous Holstein dairy cows.Twenty-one multiparous Hol-stein dairy cows with similar parity, expected date of confinement, body weight, as well as similar persistence time and milk yield of the last lactation period were selected and randomly assigned into three groups with 7 cows in each group.Cows were fed diets with the same net energy for lactation level (5.50 MJ/kg), and three different crude protein levels 12.12%(group A), 13.07%(group B) and 14.02%(group C)] during pre-partal period ( in 21 days before parturition) .The production performance and blood biochemical indexes dur-ing postpartal days 1 to 30 were investigated.The results showed as follows:1) on postpartal days 1 to 30, dry matter intake of group B were 5.41%and 5.85%higher than that in group A and C ( P<0.01) , respectively. On postpartal days 30, body weight lose of groups A, B and C were 6.30%, 5.03%and 8.22%, respectively, and group C was the highest.Group B compared the other two groups showed a trend of increasing postpartal milk production, however, there was no significant difference among groups ( P>0.05) .On postpartal days 2 to 10, lactose content of group B was 4.31%higher than that of group C ( P<0.05) .The apparent digestibility of crude protein of group B during prepartal period was 12.56%higher than that of group A ( P<0.05) .2) On postpartal days 10, 20 and 30 d, serum glucose content of group B was 31.41%, 29.47%and 21.38%higher than that of group C( P<0.05) , respectively.On the day of delivery, serum total protein content of group B was 12.98%higher than that of group C ( P<0.05) .On postpartal days 30, the contents of albumin and leptin of group B were 14.69%and 5.97%higher than that of group C ( P<0.01) , respectively.On postpartal days 20, serum triglyceride content of group B was 3.57%lower than that of group A and group C ( P<0.05) , and serum insulin content of group B was 7.26%and 12.47%lower than that of group A and group C ( P<0.01) , respectively.On postpartal days 30, serum insulin-like growth factorⅠ content of group B was 4.94%lower than that of group C ( P<0.01) .The results indicate that prepartal dietary crude protein level of 13.07%was optimal for dairy cows.