Scottish Centre for Production Animal Health and Food Safety, School of Biodiversity, One Health and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK.
School of Biodiversity, One Health and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
J Dairy Res. 2024 Feb;91(1):57-64. doi: 10.1017/S0022029924000098. Epub 2024 Mar 18.
Our objectives were to quantify the dimensions of a fully 'closed' teat canal in dry cows and to describe recovery of the teat canal between milkings in lactating cows to assess whether and when full closure is attained, since this is an important determinant of udder health. Using an ultrasound scanner, teat canal length and diameter (proximal, midpoint and distal), teat cistern width, teat end width, whole teat width and teat wall thickness in 77 dry and 39 lactating dairy cows were measured. The dry cows represented a cross section of the dry population, with days since dry off ranging from 0 to 69 (median: 27). Data from lactating cows were recorded just before milking, and every 3 h post-milking. To control for location a cross-over (parlour barn) study design was used. In dry cows, teat canal length and diameter did not vary by quarter or days since dry off, but multiparous cows had significantly wider teat canals than primiparous cows. The dry cow measurements can be used as baseline for dimensions for closed teats. In lactating cows, all teat dimensions except teat end width changed significantly during the 12-h milking cycle. Location (parlour barn) did not affect the measurements, except teat end width and teat wall thickness. Teat canal length increased after milking and returned to pre-milking values by 9 h. Proximal and midpoint teat canal diameters decreased slightly just after milking and then progressively increased to above the pre-milking values by 9 h. Distal teat canal diameter increased after milking, partially contracting by 9 h. We found that during the dry period the teat canal is in a steady state, but its diameter is not zero, while during the lactation, the teat canal is in a near constant state of remodelling.
我们的目标是量化干奶牛中完全“封闭”的乳头管的尺寸，并描述泌乳奶牛在挤奶之间乳头管的恢复情况，以评估是否以及何时达到完全封闭，因为这是乳房健康的一个重要决定因素。使用超声扫描仪测量了 77 头干奶牛和 39 头泌乳奶牛的乳头管长度和直径（近端、中点和远端）、乳头池宽度、乳头末端宽度、整个乳头宽度和乳头壁厚度。干奶牛代表了干奶牛群的一个横断面，干奶天数从 0 到 69 天（中位数：27 天）不等。泌乳奶牛的数据是在挤奶前和挤奶后每 3 小时记录的。为了控制位置，采用了交叉（牛舍）研究设计。在干奶牛中，乳头管长度和直径不因乳房象限或干奶天数而变化，但经产奶牛的乳头管比初产奶牛宽。干奶牛的测量值可以作为封闭乳头的基准尺寸。在泌乳奶牛中，除了乳头末端宽度外，所有乳头尺寸在 12 小时的挤奶周期中都发生了显著变化。位置（牛舍）除了乳头末端宽度和乳头壁厚度外，对测量值没有影响。挤奶后乳头管长度增加，并在 9 小时内恢复到挤奶前的值。挤奶后，近端和中点乳头管直径略有下降，然后逐渐增加到 9 小时时超过挤奶前的值。挤奶后，远端乳头管直径增加，9 小时时部分收缩。我们发现，在干奶期，乳头管处于稳定状态，但直径不为零，而在泌乳期，乳头管处于不断重塑的状态。
