包被蛋氨酸和蛋氨酸类似物在荷斯坦奶牛生产应用中的研究

Research of coated methionine and HMBi on production application of Holstein dairy cows

试验研究包被蛋氨酸和蛋氨酸类似物(HMBi)对荷斯坦奶牛生产性能、乳成分、产后代谢病、繁殖性能和经济效益的影响。选取450头妊娠(250±3)d、胎次相近的健康荷斯坦奶牛,随机分为3组,每组150个重复。对照组奶牛饲喂基础日粮,试验Ⅰ组、Ⅱ组奶牛分别饲喂包被蛋氨酸和蛋氨酸类似物,有效蛋氨酸含量均为9 g/(头·d)。奶牛围产期为预试期,产犊后为正式试验期,正式试验期120 d。结果显示,试验Ⅰ组和试验Ⅱ组奶牛干物质采食量和产奶量高于对照组(P>0.05)。与对照组相比,试验Ⅰ组和试验Ⅱ组乳蛋白量、乳蛋白率显著提高(P<0.05)。各组间乳脂量、乳脂率、乳糖量、乳糖率、体细胞数均差异不显著(P>0.05)。试验Ⅰ组、试验Ⅱ组奶牛亚临床酮病发病率低于对照组(P>0.05)。各组间胎衣不下发病率、真胃移位发病率、子宫炎发病率和产后瘫痪发病率差异不显著(P>0.05)。试验Ⅰ组、试验Ⅱ组奶牛21 d妊娠率高于对照组(P>0.05)。成母牛产后首次配种天数、成母牛产后平均空怀天数、怀孕成母牛平均配次无显著差异(P>0.05)。试验Ⅰ组、试验Ⅱ组奶牛经济效益高于对照组(P>0.05)。研究表明,包被蛋氨酸和蛋氨酸类似物均可显著提高荷斯坦奶牛乳蛋白量和乳蛋白率,但对生产性能、产后代谢病、繁殖性能无显著影响。

The experiment studied the effect of coated methionine and HMBi on production performance,milk composition,postpartum metabolic diseases,reproductive performance and economic benefits of Holstein dairy cows.450 healthy Holstein cows with similar parity and pregnant(250±3)d were randomly assigned into three groups with150 replicates in each group.The dairy cows in control group were fed with basal diet,coated methionine and HMBi was added in basal diet as the trial groupⅠand trial groupⅡ,respectively.The effective methionine content was 9 g/(head·d).The pre-trial lasted for peripartum period,and the trial period lasted for 120 d after calving.The results showed that the dry matter intake(DMI)and milk production of cows in groupⅠand groupⅡwere higher than those in control group(P>0.05).Compared with the control group,milk protein yield and milk protein percentage of groupⅠand groupⅡincreased significantly(P<0.05).The milk fat yield,milk fat percentage,milk lactose yield,milk lactose percentage and the milk somatic cell count(SCC)among the groups had no significant difference(P>0.05).The incidence of subclinical ketosis of cows in groupⅠand groupⅡwas lower than that of control group(P>0.05),and the incidence of retention of fetal membrane,incidence of metritis and the incidence of postpartum paralysis among the groups had no significant difference(P>0.05).The 21-day pregnant risk of adult cow of groupⅠand groupⅡwas higher than that of control group(P>0.05).Average first service date of adult cow,average days open of adult cow and average times bred of pregnant adult cow had nosignificant difference(P>0.05).The economic effect of groupⅠand groupⅡwas higher than that of control group(P>0.05).The experiment indicates that coated methionine or HMBi can increase milk protein yield and milk protein percentage,but the milk production,postpartum metabolic diseases and reproductive performance had no significant impact.