日粮DCAD与钙水平对围产前期奶牛钙代谢的影响

Effect of DCAD and calcium levels of diet on mineral nutrition of dairy cow in early perinatal period

研究旨在揭示围产前期日粮中不同阴阳离子差(DCAD)与钙水平对奶牛钙消化代谢的影响,为奶牛围产前期使用阴离子型日粮及钙添加提供依据。选择24头干奶后期中国荷斯坦奶牛随机配对分为3组,每组8头,分别在围产前期饲喂基础日粮、阴离子型日粮、阴离子型高钙日粮,定期采样分析指标。结果表明:添加阴离子盐将围产前期日粮的DCAD调为-100 mEq/kg DM,极显著增加了尿液中的钙(P<0.01),并显著降低了粪干物质中的钙(P<0.05),且极显著提高产后24 h的血钙浓度(P<0.01);而在DCAD为-100 mEq/kg DM基础上提高钙水平0.54%后,可进一步极显著的提高奶牛血钙浓度(P<0.01)。初步表明,围产前期饲喂奶牛阴离子盐可显著增加尿液钙排出量并提高肠道对钙吸收,饲喂阴离子盐和钙盐可进一步促进肠道钙吸收但降低了骨钙动员,但所有处理都对奶牛粪中磷排出量影响不显著。

This experiment was conducted to study the influence of different cation-anion difference （DCAD） and calcium levels to the digestion and metabolism of calcium in dairy cattle in the pre-perina- tal, and provide the basis for using the anionic diet and adding calcium to the dietary of dairy cattle in the pre-perinatal. In the late drying period, twenty four Chinese Holstein cows were randomly paired in- to 3 groups, each group had 8, They were respectively fed the basal diet, the anionic diet and the anion- ic dietary with high calcium in the pre-perinatal, and were regular sampled and analyzed indicators. The results show that： When DCAD was adjusted to -100 mEq/kg DM by adding a anionic salt to the diet in the pre-perinatal, calcium of the urine was extremely significantly increased （P〈0.01） , calcium of the fecal dry matter was significantly reduced （P〈0.05）, and the serum calcium concentration was ex- tremely Significantly increased 24 h after postpartum （P〈0.01）; Raising 0.54% calcium level on the ba- sis of-100 mEq/kg DM of DCAD, the serum calcium concentration of cows could be further extremelysignificantly increased （P〈O.O1）. Preliminary indication, it could significantly increase the excretion of urinary calcium and the absorption of intestinal calcium when dairy cows were fed anionic salts in ear- ly perinatal, yet it could further increase the absorption of intestinal calcium and decline the mobiliza- tion of bone calcium when they were fed anionic salts and calcium salts, but all experimental treat- ments didn＇t have a significant influence on the excretion of fecal phosphorus of dairy cows.