Anderson R R, Chavis D D
J Dairy Sci. 1986 Sep;69(9):2268-77. doi: 10.3168/jds.S0022-0302(86)80665-8.
Milk samples were collected daily from English short-hair albino guinea pigs for 21 d. Analyses included protein, fat, lactose, ash, calories, and specific gravity. All components except lactose increased in concentration gradually from the beginning to end of lactation. Protein percentage began at 6% on d 1 and was 14% on d 21. The pattern of increase was either quadratic or exponential but not rectilinear. Patterns were similar for fat, ash, and calories. Fat on d 1 was 5.6% and 9.0% on d 20. Ash was .97% on d 1 and 1.4% on d 19. Calories per gram milk were 939 on d 1, increasing gradually to 1874 on d 21. Lactose dropped from 5.5% on d 1 to 5.0% on d 2. It remained at 5% until d 6, when it began a gradual decline to .5% on d 20. Thickening of milk and increasing concentrations of protein, fat, ash, and calories, as well as a marked drop in milk volume, resulted from the precipitous decline in lactose concentration of .27%/d from d 6 to 21. Because lactose is the primary controller of osmotic equilibrium and, therefore, the primary regulator of the water content of milk, its decrease in concentration explains the decline in milk volume and the concomitant increases in fat, protein, and solids from d 6 to the end of lactation.
每天从英国短毛白化豚鼠采集乳样，持续21天。分析项目包括蛋白质、脂肪、乳糖、灰分、热量和比重。除乳糖外，所有成分的浓度在泌乳开始到结束期间逐渐增加。蛋白质百分比在第1天开始时为6%，在第21天为14%。增加模式为二次方或指数形式，但不是直线形式。脂肪、灰分和热量的模式相似。第1天的脂肪含量为5.6%，第20天为9.0%。灰分在第1天为0.97%，第19天为1.4%。每克牛奶的热量在第1天为939，逐渐增加到第21天的1874。乳糖从第1天的5.5%降至第2天的5.0%。它在5%保持到第6天，然后开始逐渐下降，到第20天降至0.5%。从第6天到第21天乳糖浓度以每天0.27%的速度急剧下降，导致牛奶变稠以及蛋白质、脂肪、灰分和热量浓度增加，同时牛奶体积显著下降。由于乳糖是渗透平衡的主要控制者，因此也是牛奶含水量的主要调节者，其浓度降低解释了从第6天到泌乳结束时牛奶体积的下降以及脂肪、蛋白质和固体含量的相应增加。
