DairyNZ, Private Bag 3221, Hamilton 3240, New Zealand.
J Dairy Sci. 2010 Jun;93(6):2541-9. doi: 10.3168/jds.2009-2949.
This study evaluated the effect of 4 criteria for determining the end-point of milking on milk yield, milk composition, completeness of milking-out, teat skin condition, somatic cell count (SCC), and the incidence of clinical mastitis (CM) in pasture-based dairy cows milked over 35 wk. The objective was to reduce milking duration without affecting milk production, SCC, or CM. Milking end-point treatments were as follows: cluster removed at a milk flow rate of 0.2 kg/min (ACR200); cluster removed at a milk flow rate of 0.4 kg/min (ACR400); cluster removed at a milk flow rate of 0.2 kg/min or at a maximum cluster attachment time from d 5 of lactation (MaxTEarly); and cluster removed at a milk flow rate of 0.2 kg/min until an average of 63+/-21 d in milk, then cluster removed at a milk flow rate of 0.2 kg/min or a maximum cluster attachment time (MaxTPeak). Maximum cluster attachment times were set at 7.5 min and 5.4 min for morning and afternoon milkings, respectively. Cows (approximately 94/treatment) were assigned to treatment at calving and milked twice daily at intervals of 9 and 15 h. Milking duration was shorter for ACR400, MaxTEarly, and MaxTPeak compared with ACR200. During wk 1 to 15, milk, protein, and lactose yields were less for MaxTEarly than for ACR400 and MaxTPeak, but not different from ACR200. During wk 16 to 35 and over the entire experiment, total milk, fat, protein, and lactose yields did not differ among treatments. Teat condition did not differ among the 4 treatments. Postmilking strip yield in wk 12 was greatest for MaxTEarly and least for ACR200; at wk 27, however, treatment had no effect on the completeness of milking-out. No differences were observed in either teat condition or the proportion of cows with at least 1 case of CM during the 35 wk. Somatic cell count was low across all treatments, but highest for ACR400. Increasing the automatic cluster remover threshold setting from 0.2 to 0.4 kg/min decreased milking duration without affecting milk production, CM, or teat condition. Combining a cluster removal milk flow threshold setting with a maximum cluster attachment time, when applied from either early lactation or from peak lactation, reduced milking duration without affecting milk production, CM, or SCC. Both strategies have potential to improve milking efficiency in dairy herds in which premilking preparation is minimal.
本研究评估了 4 种确定挤奶终点的标准对产奶量、乳成分、挤奶完成度、乳头皮肤状况、体细胞计数 (SCC) 和临床乳腺炎 (CM) 的影响，研究对象为在牧场上饲养的奶牛，挤奶时间超过 35 周。研究目的是在不影响产奶量、SCC 或 CM 的情况下缩短挤奶时间。挤奶终点处理如下：当奶流率达到 0.2 公斤/分钟时（ACR200）移除奶杯；当奶流率达到 0.4 公斤/分钟时（ACR400）移除奶杯；当奶流率达到 0.2 公斤/分钟或从泌乳第 5 天开始最大奶杯连接时间时（MaxTEarly）移除奶杯；当平均泌乳天数达到 63+/-21 天时，奶流率为 0.2 公斤/分钟，然后当奶流率达到 0.2 公斤/分钟或最大奶杯连接时间时（MaxTPeak）移除奶杯。早晨和下午的最大奶杯连接时间分别设定为 7.5 分钟和 5.4 分钟。奶牛（每个处理组约 94 头）在分娩时被分配到处理组，并每隔 9 小时和 15 小时进行两次挤奶。与 ACR200 相比，ACR400、MaxTEarly 和 MaxTPeak 的挤奶时间更短。在第 1 周到第 15 周期间，与 ACR400 和 MaxTPeak 相比，MaxTEarly 的奶、蛋白质和乳糖产量较低，但与 ACR200 无差异。在第 16 周到第 35 周和整个实验期间，4 种处理方式的总奶、脂肪、蛋白质和乳糖产量没有差异。4 种处理方式的乳头状况没有差异。在第 12 周时，MaxTEarly 的挤奶后乳头带产量最大，ACR200 的产量最小；然而，在第 27 周时，处理方式对挤奶完成度没有影响。在 35 周的时间里，无论是乳头状况还是至少有 1 例 CM 的奶牛比例都没有差异。所有处理方式的体细胞计数都较低，但 ACR400 的最高。将自动脱杯器阈值设置从 0.2 公斤/分钟增加到 0.4 公斤/分钟，可以缩短挤奶时间，而不影响产奶量、CM 或乳头状况。从泌乳早期或泌乳高峰期开始，将奶流阈值设置与最大奶杯连接时间相结合，可以缩短挤奶时间，而不影响产奶量、CM 或 SCC。这两种策略都有可能提高牧场挤奶效率，而牧场挤奶的前期准备工作很少。
