铬对泌乳期奶牛的生产性能和主要生理指标的影响

研究了泌乳期奶牛日粮中添加吡啶羧酸铬或赖氨酸铬对其生产性能和血液主要生理指标的影响。选择75头泌乳前期（〈80d）的荷斯坦奶牛随机分为试验组A、B和对照组C。试验组A和B每天日粮中分别补充吡啶羧酸铬和赖氨酸铬，供试期间对照组C不添加有机铬。结果表明：铬可提高泌乳期奶牛的生产性能，增强和改善泌乳奶牛的免疫力和应激状态。试验组A和试验组B泌乳量高于对照组C（P〈0．01）；试验组B血清中的甘油三酯的浓度低于对照组C（P〈0．05）；试验组A血清中胰岛素浓度低于对照组C（P〈0．01）；试验组A和试验组B血清中葡萄糖浓度都高于对照组C（P〈0．01）；试验组A和试验组B血清中皮质醇的浓度分别比对照组C低7．21nmol／L和4．92nmol／L，试验组A和试验组B血清中IgG的浓度分别比对照组C高2．1g／L和3．1g／L。

Effect of Chelated Chromium Supplementation on Lactation Performance and Blood Parameters of Dairy Cows during the Lactating Period

The objective of this study was to determine the effects of chelated chromium(chromium-picolinate or chromium-lysine) supplementation on lactation performance and some blood components of Holstein cows during the lactating period.Seventy five multiparous lactating Holstein cows(80 days post-partum) used in this study were divided equally into three groups(25 cows/treatment) and were randomly allocated to one of three treatment diets.Diet A,basal diet,with chromium-picolinate added at manufacturer's recommended level(0.6g /head per day). Diet B,basal diet,with chromium-lysine(0.076g /head per day).Diet C,was basal diet without chromium(Cr) added and served as a control.The result of this study showed the supplement of chromium to the diet of cattle contributed to the increase of milk yield and may contribute to the improvement of the immune status of stressed dairy cows.In comparison with the diet C,milk production of diet A and diet B were both increased(P<0.01),insulin concentration in blood of diet A led to depressed(P<0.01)and glucose concentrations in blood of diet A and diet B were higher than that of treatment diet C(P<0.01).The mean Cortisol concentration in blood of diet A and diet B decreased by 7.21nmol/L,4.92nmol/L,respectively,and the mean IgG concentration in blood of diet A and diet B increased by 2.1g/L and 3.1g/L,respectively,compared with diet C.