Bruckmaier R M, Ritter C, Schams D, Blum J W
Institut für Tierzucht, Universität Bern, Schweiz.
J Dairy Res. 1994 Nov;61(4):457-66. doi: 10.1017/s0022029900028387.
Forty-four goats were milked and milk flow recorded without or with 1 min manual prestimulation in early, mid and late lactation. Ultrasound measurements of cross sections of the whole mammary gland were performed in a water bath. In additional experiments with 15 goats, milk flow was recorded and frequent blood samples were taken for the determination of oxytocin and prolactin concentrations. Milk yield increased from the first to the third lactation and decreased markedly during the course of lactation. Average and peak milk flow rates were closely related to the actual milk yield. The ultrasound cisternal area was 27.4 +/- 1.5% of the entire udder half cross section. Milking characteristics were scarcely different without or with prestimulation, although oxytocin was released within 30 s after the start of prestimulation, whereas oxytocin concentrations without prestimulation increased only after the start of milking. Concentrations of prolactin were higher during July and August than in April, and increased similarly with or without prestimulation during milking. In contrast to dairy cows, prestimulation and an opportune release of oxytocin during milking does not significantly influence the course of milk flow in goats, and this is probably because large amounts of cisternal milk allow milk ejection to be induced only after the start of milking without causing bimodal or otherwise reduced milk flow.
在泌乳早期、中期和晚期，对44只山羊进行挤奶，并记录有无1分钟手动预刺激时的奶流情况。在水浴中对整个乳腺的横截面进行超声测量。在另外15只山羊的实验中，记录奶流情况，并频繁采集血样以测定催产素和催乳素浓度。产奶量从第一胎到第三胎增加，在泌乳过程中显著下降。平均奶流率和峰值奶流率与实际产奶量密切相关。超声测量的乳池面积占整个乳房半横截面的27.4 +/- 1.5%。有无预刺激时的挤奶特性几乎没有差异，尽管预刺激开始后30秒内催产素就会释放，而无预刺激时催产素浓度仅在挤奶开始后才会增加。7月和8月的催乳素浓度高于4月，挤奶时有或无预刺激时催乳素浓度的增加情况相似。与奶牛不同，预刺激和挤奶时适时释放催产素对山羊的奶流过程没有显著影响，这可能是因为大量的乳池奶使得只有在挤奶开始后才能引发排乳，而不会导致双峰奶流或奶流减少。
