Shearn M F, Hillerton J E
Institute for Animal Health, Compton Laboratory, Newbury, UK.
J Dairy Res. 1996 Nov;63(4):525-32. doi: 10.1017/s0022029900032064.
Teat orifice hyperkeratosis, a commonly observed condition in dairy cows, has been considered a consequence of machine milking and the degree of hyperkeratosis may be increased by a poor milking system. A fully illustrated technique is described which uses a scoring system from 0 for a perfect orifice to 5 for an orifice significantly enlarged with extensively protruding fronds of teat duct keratin. A range of scores found in 25 commercial dairy herds is presented. The scores have been averaged for each cow and the markedly skewed distribution corrected by a square root transformation. This scoring procedure allows comparative measures of hyperkeratosis within and between herds. An 8-fold difference (0.17-1.31) in herd average score was found. Within all herds the score increased with lactational age of the animals and peaked, for any lactation, some 3-4 months post partum, declining as the animals dried off. There was no significant relationship between mean somatic cell count and degree of hyperkeratosis at the herd level. This implies that such chronic pathological changes are unlikely to be related to the level of intramammary infection. It appeared that some hyperkeratosis is an obvious and probably natural response to milking and occurs in a significant proportion of animals in all herds although often only to a slight degree. Much more hyperkeratosis may be a measure of the performance and management of the herd. The genetic influence is unknown. Higher yielding cows will score higher as they milk for longer, but generally high scores may reflect consistent and possibly considerable overmilking. Hyperkeratosis may be an indicator of the quality of management and show the level of attention being paid to the welfare of the herd.
乳头开口处角化过度是奶牛中常见的一种情况，一直被认为是机械挤奶的结果，而不良的挤奶系统可能会加剧角化过度的程度。本文描述了一种配有完整插图的技术，该技术使用一种评分系统，从完美乳头开口的0分，到乳头管角质有大量突出叶状物且显著扩大的乳头开口的5分。文中呈现了在25个商业奶牛场中发现的一系列评分。对每头奶牛的评分进行了平均，并通过平方根变换校正了明显偏态的分布。这种评分程序可以对牛群内部和不同牛群之间的角化过度情况进行比较测量。发现牛群平均得分存在8倍的差异（0.17 - 1.31）。在所有牛群中，评分随着动物的泌乳年龄增加而升高，并在任何一个泌乳期产后约3 - 4个月达到峰值，随着动物干奶而下降。在牛群层面，平均体细胞计数与角化过度程度之间没有显著关系。这意味着这种慢性病理变化不太可能与乳腺内感染水平相关。似乎一些角化过度是对挤奶的一种明显且可能是自然的反应，在所有牛群的很大一部分动物中都会出现，尽管通常程度较轻。更多的角化过度情况可能是牛群性能和管理的一种衡量指标。遗传影响尚不清楚。高产奶牛由于挤奶时间更长，得分会更高，但一般来说高分可能反映出持续且可能相当严重的过度挤奶。角化过度可能是管理质量的一个指标，显示出对牛群福利的关注程度。
