Castillo V, Such X, Caja G, Casals R, Salama A A K, Albanell E
Grup de Recerca en Remugants, Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
J Dairy Sci. 2009 Aug;92(8):3684-95. doi: 10.3168/jds.2008-1937.
The long- and the short-term effects of omitting 2 milkings weekly in early (wk 8 to 14) and mid lactation (wk 15 to 22) were investigated in an experiment conducted with a total of 58 dairy ewes (40 Manchega and 18 Lacaune). Ewes submitted to 2 milking omissions were milked twice daily from Monday to Friday (0800 and 1800 h), and once daily on Saturday and Sunday (1600 and 1400 h, respectively). Individual data were collected for milk yield (weekly), milk composition (biweekly), and somatic cell count (SCC; monthly). Omitting 2 milkings per week in early lactation tended to decrease milk yield in Manchega ewes (-15%), whereas no effects were observed in Lacaune ewes. Averaged milk composition was not modified by milking omissions in either breed. Milking omissions in late lactation did not affect milk yield and milk composition in either breed. The SCC were unaffected by milking omissions in both breeds and in both stages of lactation. A sample of 22 Manchega and 11 Lacaune ewes were used to evaluate the short-term (daily) effects of the 2 milking omissions per week on milk yield and composition, udder health, and tight junction permeability, both in early lactation (wk 12) and in mid lactation (wk 20). Milking omission decreased milk yield, milk fat, and milk lactose contents on the first omission day in both breeds, with losses being more noticeable in early lactation than in mid lactation. Milk protein content and SCC did not vary by effect of the weekend milking omissions. After restoring the twice-daily milking routine on Monday, milk yield showed a compensatory increase that was greater in the large-cisterned than in the small-cisterned ewes, which allowed milk yield to return to Friday values in both breeds. Milk fat content increased during Sunday and Monday, reestablishing Friday values thereafter in both breeds. Weekend milking omissions in early lactation caused tight junction leakiness in both breeds, but mammary epithelia adapted to extended milking intervals when applied successively, recovering their tight state after milking. In mid lactation, the mammary tight junction showed leakiness only in Manchega ewes. In conclusion, 2 milkings per week could be omitted with no negative effects on milk yield, milk composition, and milk SCC values in large-cisterned dairy ewes, as observed in Lacaune and large-cisterned Manchega ewes. Losses in milk yield could be reduced if milking omissions were done from mid lactation in small-cisterned ewes.
在一项对总共58只奶羊（40只曼彻格羊和18只拉库纳羊）进行的实验中，研究了在泌乳早期（第8至14周）和中期（第15至22周）每周少挤两次奶的长期和短期影响。每周少挤两次奶的母羊在周一至周五每天挤奶两次（08:00和18:00），在周六和周日每天挤奶一次（分别为16:00和14:00）。收集了个体产奶量（每周）、奶成分（每两周）和体细胞计数（SCC；每月）的数据。在泌乳早期，曼彻格羊每周少挤两次奶往往会使产奶量下降（-15%），而拉库纳羊未观察到影响。两个品种的平均奶成分均未因少挤奶而改变。泌乳后期少挤奶对两个品种的产奶量和奶成分均无影响。两个品种在泌乳的两个阶段，SCC均不受少挤奶的影响。选取22只曼彻格羊和11只拉库纳羊样本，评估在泌乳早期（第12周）和中期（第20周）每周少挤两次奶对产奶量和成分、乳房健康及紧密连接通透性的短期（每日）影响。少挤奶在两个品种的首次少挤奶日降低了产奶量、乳脂和乳糖含量，泌乳早期的损失比中期更明显。乳蛋白含量和SCC并未因周末少挤奶而变化。周一恢复每日两次挤奶常规后，产奶量出现补偿性增加，大贮乳池母羊的增加幅度大于小贮乳池母羊，使两个品种的产奶量均恢复到周五的水平。乳脂含量在周日和周一增加，之后两个品种均恢复到周五的水平。泌乳早期周末少挤奶导致两个品种的紧密连接渗漏，但乳腺上皮细胞在连续少挤奶时能适应延长的挤奶间隔，挤奶后恢复紧密状态。在泌乳中期，乳腺紧密连接仅在曼彻格羊中出现渗漏。总之，正如在拉库纳羊和大贮乳池曼彻格羊中观察到的那样，大贮乳池奶羊每周少挤两次奶对产奶量、奶成分和奶SCC值没有负面影响。对于小贮乳池母羊，如果从泌乳中期开始少挤奶，产奶量损失可能会减少。
