Fleet I R, Mepham T B
J Dairy Res. 1985 May;52(2):229-37. doi: 10.1017/s0022029900024092.
Changes in mammary blood flow, arterial and venous plasma concentrations of glucose and individual amino acids, udder volume, and milk yield and composition were measured at intervals throughout lactation in four Friesland ewes. Milk yields peaked 50-80 d post partum and declined by 40% within 3 months. Neither mammary blood flow (43.3 +/- 5.8 (s.e.m.) ml/100 cm3 X min) nor udder volume changed significantly throughout the period of study, but for three ewes the 'mammary blood flow: milk yield' ratio increased from 300 (peak yield) to 570 (late lactation). Mammary glucose uptake remained essentially constant throughout lactation despite a 50% decline in lactose output. Arterial concentrations of glucose were much lower at peak yield than in late lactation. Mammary amino acid uptake conformed quite closely to 'essential' and 'non essential' categories previously defined for goats and cows, the degree of balance with output in milk protein being similar at all stages of lactation. For several amino acids arterial concentrations and arteriovenous differences were significantly positively correlated: the changes in arterial concentrations with lactation stage were also correlated for some amino acids. Apart from the intrinsic value of such studies on a breed of ewe increasingly used for dairy purposes, the Friesland ewe appears well suited for use in quantitative metabolic studies on lactation.
在整个泌乳期，对4只弗里斯兰母羊每隔一段时间测量乳腺血流量、动脉和静脉血浆中葡萄糖及各种氨基酸的浓度、乳房体积、产奶量及乳汁成分。产奶量在产后50 - 80天达到峰值，3个月内下降了40%。在整个研究期间，乳腺血流量（43.3±5.8（标准误）ml/100 cm³×min）和乳房体积均无显著变化，但有3只母羊的“乳腺血流量：产奶量”比值从300（产奶量峰值时）增至570（泌乳后期）。尽管乳糖产量下降了50%，但整个泌乳期乳腺对葡萄糖的摄取基本保持恒定。产奶量峰值时动脉血葡萄糖浓度远低于泌乳后期。乳腺对氨基酸的摄取与先前为山羊和奶牛定义的“必需”和“非必需”类别相当吻合，在泌乳各阶段，氨基酸摄取与乳蛋白输出的平衡程度相似。对于几种氨基酸，动脉血浓度与动静脉差值显著正相关：某些氨基酸的动脉血浓度随泌乳阶段的变化也存在相关性。除了这类针对越来越多地用于产奶的母羊品种研究的内在价值外，弗里斯兰母羊似乎非常适合用于泌乳的定量代谢研究。
