干奶期不同能量水平对奶牛血中神经肽 Y和生长激素浓度的影响

将健康围产期奶牛30头随机分为3组．预产前28d按奶牛营养需要分别饲喂100％、120％、80％能量日粮，产后各组奶牛均饲喂标准的产奶日粮，至产后56d结束，观测干奶期不同能量摄入水平对围产期健康奶牛血中神经肽Y和生长激素浓度的影响。结果表明，干奶期低能量日粮饲喂，奶牛血中神经肽和生长激素浓度均高于其他2组，从产前14d至产后28d组间差异显著（P〈0.01；P〈0.05），提示低能量饲料饲喂干奶期奶牛，产后能量负平衡得到缓解。

Effect of Energy Intake during the Dry Period on Plasma Concentrations of Neuropeptide Y and Growth Hormone in Peripartum Diary Cows

The objective of the present study was to investigate the effect of energy intake during the dry period on plasma concentrations of neuropeptide Y (NPY) and growth hormone (GH) in peripartum diary cows .Thirty healthy cows were randomly allocated into three groups and fed 100% energy diet (standard diets), 120% energy diet and 80% energy diet,respectively, beginning at 28th day before parturition. After calving, all the cows were offered the lactation ration ad libitum until 56th day postpartum. The results indicated that the cows fed with low energy diet during the dry period had the significant increase in plasma concentrations of NPY and GH,as compared with the cows fed with 120%energy diet and 100% energy diet. It is concluded that low energy diet during the dry period may effectively reduce negative energy balance caused by the onset of copious milk secretion and an inadequate increase in voluntary food intake.