热应激条件下日粮中添加氯化钾对奶牛生产性能和血液指标的影响

试验旨在研究热应激条件下,日粮中添加氯化钾对奶牛生产性能和血液理化指标的影响。选取45头荷斯坦泌乳牛,随机分为3组(n=15),在高温季节进行饲养试验,对照组饲喂基础日粮,试验Ⅰ、Ⅱ组分别在基础日粮中添加50、100 g/d氯化钾。试验结果表明,各组间血清游离脂肪酸(NEFA)、葡萄糖(GLU)、尿素氮(BUN)含量差异均不显著(P0.05);试验Ⅰ、Ⅱ组β-羟丁酸(BHBA)含量显著低于对照组(P0.05),但试验Ⅰ、Ⅱ组之间差异不显著(P0.05);试验Ⅰ、Ⅱ组平均日产奶量分别比对照组高1.6(P0.05)和0.7 kg(P0.05);各组间乳成分无显著变化(P0.05)。因此,夏季奶牛日粮中添加氯化钾可减缓产奶量的下降。

Effect of Dietary Supplementation Potassium Chloride on the Production Performance and Blood Indicators of Dairy Cows in the Condition of Heat Stress

45 Holstein lactaing cows with similar lactaion period, calving number and milk yield were randomly divided into 3 groups(n=15), in order to research the effects of diet adding potassium chloride on production performance and blood indexes of lactating cows during July to September. The diets of three experimental groups were basal diet(comprising corn silage, green hay and concentrates) (control group), basal diet＋50 g potassium chloride (groupⅠ) and basal diet＋100 g potassium chloride (groupⅡ) respectively. The results showed that there were no significant differences between groups in content of free fatty acids(NEFA), glucose(GLU) and urea nitrogen(BUN) in serum (P>0.05). β-hydroxybutyrate (BHBA) content was significantly higher in control group than in group Ⅰand Ⅱ(P<0.05),whereas no significant difference was found between group Ⅰand Ⅱ. Compared with the control group, decreasing degree of daily milk yield was less 1.6 kg (P<0.05) and 0.7 kg (P<0.05) for group Ⅰand Ⅱrespectively. There were no significant difference between groups in milk composition (P>0.05).The results indicated that potassium chloride supplementation can relieve the decreasing of milk production in summer.