The Influences Of Potassium And Chromium On Production Performance And Blood Indicators Of Cows In Summer And Winter

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 and Chromium Picolinate on production performance and blood indexes of lactating cows during summer and winter. The diets of three experimental groups were basal diet(comprising corn silage, green hay and concentrates) (control group), basal diet+50g potassium chloride or 7mg/d Chromium Picolinate (groupⅠ) and basal diet+100g potassium chloride or 14mg/d Chromium Picolinate (groupⅡ) respectively. The results showed that:(1) 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 groupⅠandⅡ(P<0.05),whereas no significant difference was found between groupⅠandⅡ; Compared with the control group, decreasing degree of daily milk yield was less 1.6kg (P<0.05) and 0.7kg (P<0.05) for groupⅠandⅡrespectively; There were no significant difference between groups in milk composition (P>0.05),dietary supplementation potassium chloride in summer. The results indicated that potassium chloride supplementation can relieve the decreasing of milk production in summer.(2) there were no significant differences between groups in content of NEFA,GLU,BUN and BHBA in serum (P>0.05); increasing of daily milk yield was 0.67kg(P>0.05) and 0.11kg(P>0.05) for control group andⅡrespectively , decreasing of daily milk yield was 0.3kg(P>0.05) for groupⅠ; There were no significant difference between groups in milk composition (P>0.05),dietary supplementation potassium chloride in winter.(3) there were no significant differences between groups in content of Chromium(Gr) glucose(GLU) glucose(GLU)and total cholesterol(TCH) in serum (P>0.05); increasing of daily milk yield was 1.06kg(P<0.05) for groupⅠ, Compared with the control group, increasing of daily milk yield was 0.04kg(P>0.05) for groupⅡ; There were no significant difference between groups in milk composition (P>0.05), dietary supplementation Chromium Picolinate in summer. The results indicated that Chromium Picolinate supplementation can relieve the decreasing of milk production in summer.(4) there were no significant differences between groups in content of Chromium(Gr) glucose(GLU) glucose(GLU)and total cholesterol(TCH) in serum (P>0.05); Compared with the control group, decreasing of daily milk yield was 0.05kg (P>0.05) and 0.32kg (P>0.05) for groupⅠandⅡrespectively; There were no significant difference between groups in milk composition (P>0.05), dietary supplementation Chromium Picolinate in winter. The results indicated that potassium chloride and Chromium Picolinate supplementation can relieve the decreasing of milk production in summer.(5) potassium chloride and Chromium Picolinate supplementation can significant relieve the decreasing of milk production in summer.