Buckley B A, Herbein J H, Young J W
J Dairy Sci. 1982 Mar;65(3):371-84. doi: 10.3168/jds.S0022-0302(82)82201-7.
Both intravenous single injections of 6-tritium labeled glucose and primed continuous infusions of uniformly labeled carbon-14 glucose were applied to four nonpregnant Saanen goats. Four sequential treatments were high milk production, low milk production, "dry" with no milk production, and fasting during the dry period. The diet was 25% chopped alfalfa hay and 75% grain, and by design feed intake decreased sequentially (1.85, 1.49, .80) and 0 kg/day) with the progression from high production to fasting. Glucose irreversible loss averages from single injections of tritium labeled glucose were 199, 169, 96, and 58 mg/min for respective treatments; similar averages from continuous infusions of carbon labeled glucose for the first three treatments were 164, 132, and 76 mg/min, or about 20% less. Other blood glucose kinetic parameters were estimated after single injections, and averages declined from 5.9 to 4.5 g for pool size, 315 to 134 mg/min for total entry rate, and 115 to 76 mg/min for recycling as goats went from high production to fasting. Transfer of blood glucose to milk constituents was determined by continuous infusion. Transfer quotients for lactose were 73% for high production and 67% for low production; for casein they were 1.8 and 1.9%. The percentage of glucose irreversible loss accounted for in lactose was 31% for high production and 17% for low production whereas less than .2% was in casein.
对四只未怀孕的萨能山羊分别进行了静脉单次注射6-氚标记葡萄糖和初始连续输注均匀标记的碳-14葡萄糖的操作。依次进行了四种处理：高产奶量、低产奶量、“干奶期”无奶产量以及干奶期禁食。日粮为25%切碎的苜蓿干草和75%谷物，并且按照设计，随着从高产到禁食阶段的推进，采食量依次减少（分别为1.85、1.49、0.80和0千克/天）。单次注射氚标记葡萄糖后葡萄糖不可逆损失的平均值在各处理中分别为199、169、96和58毫克/分钟；前三种处理连续输注碳标记葡萄糖的类似平均值分别为164、132和76毫克/分钟，约低20%。单次注射后还估计了其他血糖动力学参数，随着山羊从高产进入禁食状态，池大小的平均值从5.9克降至4.5克，总进入速率从315毫克/分钟降至134毫克/分钟，再循环从115毫克/分钟降至76毫克/分钟。通过连续输注测定了血糖向乳成分的转移。乳糖的转移系数高产时为73%，低产时为67%；酪蛋白的转移系数分别为1.8%和1.9%。高产时乳糖中葡萄糖不可逆损失所占百分比为31%，低产时为17%，而酪蛋白中的不到0.2%。
