Hillerton J E, Ohnstad I, Baines J R, Leach K A
Institute for Animal Health, Compton Laboratory, Newbury, UK.
J Dairy Res. 2000 Aug;67(3):309-17. doi: 10.1017/s0022029900004283.
We have investigated the responses of cow teats to machine milking in a study of relatively newly installed commercial milking parlours fitted with one of two types of milking cluster. The first was a common type with a large claw volume (> 200 ml), 15-16 mm i.d. long milk tube, 10 mm short pulse tube, cluster weight < 3-2 kg and used alternate pulsation. The second was a more traditional type with a 150 ml claw bowl volume, 13.5 mm i.d. long milk tube, 8 mm short pulse tube, cluster weight approximately 3.5 kg and used simultaneous pulsation. We scored approximately 50 cows in each of 20 herds, all within 60 s of cluster removal, for changes from the premilking teat condition: teat colour (creation of reddening or blueness), firmness, thickening at the base of the teat associated with the position of the liner mouthpiece, and whether the teat duct orifice was open. There were statistically significant differences in the proportion of cows displaying these four alterations in teat condition between herds using the two types of cluster. The more common type of cluster was always associated with better teat condition. The cause and effect of poorer teat condition have not been fully established and are likely to be multifactorial. The principal risk factors may be cluster weight, overmilking, vacuum applied during the overmilking phase and the design of the liner mouthpiece.
在一项针对相对新安装的商业挤奶厅的研究中，我们调查了奶牛乳头对机械挤奶的反应，这些挤奶厅配备了两种类型的挤奶杯组中的一种。第一种是常见类型，奶爪容积大（>200毫升），内径15 - 16毫米的长奶管，10毫米的短脉冲管，杯组重量<3 - 2千克，采用交替脉动。第二种是更传统的类型，奶爪碗容积为150毫升，内径13.5毫米的长奶管，8毫米的短脉冲管，杯组重量约3.5千克，采用同步脉动。我们在20个牛群中，对每群约50头奶牛在取下杯组后的60秒内进行评分，观察挤奶前乳头状况的变化：乳头颜色（变红或变蓝）、硬度、与内衬吸口位置相关的乳头基部增厚情况，以及乳头管开口是否打开。使用两种类型杯组的牛群中，出现这四种乳头状况改变的奶牛比例存在统计学上的显著差异。较常见类型的杯组总是与更好的乳头状况相关。乳头状况较差的因果关系尚未完全明确，可能是多因素的。主要风险因素可能是杯组重量、过度挤奶、过度挤奶阶段施加的真空以及内衬吸口的设计。
