Wilde C J, Henderson A J, Knight C H, Blatchford D R, Faulkner A, Vernon R G
J Anim Sci. 1987 Feb;64(2):533-9. doi: 10.2527/jas1987.642533x.
In two separate experiments, lactating goats were milked unilaterally thrice daily instead of twice daily for periods of 13 and 37 wk, starting at 2 to 5 wk after parturition. The other gland was milked twice daily throughout. In both experiments thrice-daily milking increased milk yield significantly. In the first experiment, after 37 wk the amounts of RNA and DNA, rate of cell proliferation and activities of several enzymes per cell were greater in the thrice-milked gland (P less than .05). In the second experiment, after 9 or 10 d of thrice-daily milking the activities of several key mammary enzymes per cell measured in biopsy samples had increased in the thrice-milked but not the twice-milked gland. After 13 wk of thrice-daily milking, the DNA content of the glands and the activity per cell of the key enzymes was the same in both glands, showing that the synthetic capacity of the gland was being used more effectively in the treated gland. These results indicate that several mechanisms contributed to the increased milk yield induced by thrice-daily milking.
在两项独立实验中，从分娩后2至5周开始，对泌乳山羊单侧乳房每天挤奶三次而非两次，持续13周和37周。另一侧乳房则始终每天挤奶两次。在两项实验中，每天三次挤奶均显著提高了产奶量。在第一项实验中，37周后，每天挤奶三次的乳房中RNA和DNA含量、细胞增殖速率以及每个细胞中几种酶的活性更高（P<0.05）。在第二项实验中，每天三次挤奶9或10天后，活检样本中检测到的每天挤奶三次的乳房中每个细胞的几种关键乳腺酶活性增加，而每天挤奶两次的乳房中则未增加。每天三次挤奶13周后，两个乳房的DNA含量以及关键酶的每个细胞活性相同，表明处理过的乳房中腺体的合成能力得到了更有效的利用。这些结果表明，几种机制促成了每天三次挤奶诱导的产奶量增加。
