补充2-羟基-4-甲硫基-丁酸异丙酯对奶牛生产性能及血液生化指标的影响

Effects of Dietary Supplementation of 2-hydroxy-4-(methylthio) Butanoic Acid Isopropyl Ester on Productive Performance and Blood Biochemical Indexes in Dairy Cows

本试验旨在探讨日粮补充2-羟基-4-甲硫基-丁酸异丙酯(HMBi)以平衡日粮赖氨酸和蛋氨酸对奶牛生产性能及血液生化指标的影响。将45头处于干奶后期2～3胎的荷斯坦奶牛,随机分配到A、B和C组中,每组15头奶牛。其中A组为对照组,整个试验期饲喂基础日粮;B组于产犊当天(产后第1天)开始、C组于产前15天开始在基础日粮中添加HMBi,以平衡日粮赖氨酸和蛋氨酸。试验期为产前15天到产后第90天。试验结果显示:与对照组相比,B和C组产奶量分别提高了3.24和3.97kg/d。C组乳脂率显著高于对照和B组(P<0.05),而对照和B组乳脂率差异不显著(P>0.05);B和C组均提高了乳脂的绝对产量,分别较对照组提高了0.14和0.18kg/d。不同组间的乳蛋白率差异不显著(P>0.05),但与对照组相比,B和C组乳蛋白的绝对产量分别提高了0.10和0.09kg/d。产后第90天,各组奶牛血清葡萄糖含量的差异不显著(P>0.05)。补充HMBi对奶牛牛奶尿素氮(MUN)、血清总氨基酸(TAA)、血清尿素氮(BUN)都没有显著影响(P>0.05),但有降低BUN和MUN的趋势。补充HMBi对游离脂肪酸(NEFA)、总胆固醇(TC)和甘油三酯(TG)含量的影响不显著(P>0.05),但有降低奶牛血清NEFA和TC的趋势。结果提示,通过补充HMBi来平衡日粮赖氨酸和蛋氨酸能显著提高奶牛的生产性能,具有改善奶牛代谢状况的趋势。

The trial was conducted to study the effects of supplementation of 2-hydroxy-4-（methylthio） butanoic acid isopropyl ester （HMBi） for balancing dietary Lys-Met on productive performance and blood biochemical indexes in dairy cows. Fortyfive Holstein dairy cows with 2--3 embryoes in late dry period were selected and assigned randomly into A, B and C group which contained 15 dairy cows. Group A as control group was fed a basal diet during total experimental period; for balancing dietary Lys-Met, group B was fed the basal diet with HMBi supplementation started from calving （1 d post-partum）, and the group C was fed the basal diet with HMBi supplementation from 15 d pre-partum. The experimental period was from 15 d pre-partum to 90 d post-partum. The results showed as follows： compared with control group, the milk yields in groups B and C were significantly increased by 3.24 and 3.97 kg/d, respectively （P〈0.05）. The milk fat percentage in group C was significantly higher than that in control group and group B （P〈0.05）, and there was no significant difference between control group and group B （P〉0.05）. The milk fat absolute yields in groups B and C were significantly increased by 0.14 and 0.18 kg/d （P〈0.05） compared with control group, respectively. Although there was no significant difference in milk protein percentages among groups （P〉0.05）, the milk protein yield of groups 13 and C was 0.10 and 0.09 kg/d higher than that in control group （P〈0.05）, respectively. There was no significant difference of serum glucose among all groups at day 90 of post-partum （P 〉 0.05）. HMBi supplementation in dairy cows had no significant effects on milk urea nitrogen （MUN）, blood urea nitrogen （BUN） and serum total amino acid （P〉0.05） ; however, there was a decreasing tendency in BUN and MUN. The concentrations of serum non-esterified fatty acid （NEFA）, triglyceride （TC） and total cholesterol were not significantly influenced by dietary HMBi supplementation （P〉0.05）, but there was a trend to decrease the NEFA and TC. The results indicated that balancing dietary Lys-Met by supplementation with HMBi could improve productive performances, and there was a tendency to improve metabolic conditions.