高温环境乳牛日粮电解质平衡调节与调剂时间

Administration Time and Changing of Dietary Electrolyte Balance for Dairy Cows in Hot Environments

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。

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 Ca^2＋ 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.