【摘要】 选择泌乳中期奶牛10头,随机分成A和B组,设定两组日粮阴阳离子差(DCAD)均为32.4/100g DM,A组日间三次给予,B组是早晨一次添加,研究日粮电解质平衡与调剂时间对热应激奶牛生产、酸碱平衡的影响。结果表明,B组采食量和产奶量分别提高16.7%(P<0.05)和19.4%(P<0.01);乳蛋白、乳脂、乳糖以及乳中矿物质含量亦有增加的趋势,但组间无显著影响;14:00尾静脉血中B组N a、K、Ca离子浓度和血pH以及pCO2和HCO3-浓度组间无明显差异,B组碱储增加,为正值,但组间差异不显著;尿pH升高(P<0.05),N a+、K+、C l-排出量有增加趋势,尿中电解质平衡,DCAD降低。更多还原

【Abstract】 Ten mid-lactation Holstein cows were assigned randomly to A or B,and administration time-dependent influence of dietary cation-anion difference on performance,acid-base balance under summer condition in dairy cows were studied with the same ion salt.The results indicated that administration time-dependent of dietary cation-anion difference significantly influenced the performance of heat-stress dairy cows.Intake of DM and 4% FCM increased 16.7%（P<0.05）and 19.4%（P<0.01）,respectively;Expect of NFC（P<0.01）,milk fat、protein、lactose and rough mineral were not altered by administration time of dietary cation-anion difference;Blood samples taken from the caudle vein at 14:00 indicated that blood Na⁺、K⁺ and Ca²⁺ and blood pH、carbon dioxide partial pressure and HCO₃^-concentration were not altered by the administration time,Blood base excess increased in B,but the difference between groups was not significant.Urine pH was increased（P<0.05）,and the excretion of urinary Na⁺、K⁺ and Cl^-had the tendency to be raised.And the urine electrolyte balance（Na⁺K-Cl） was decreased.更多还原