Institute of Animal Science, Department of Physiology and Hygiene, University of Bonn, Bonn 53115, Germany; Center of Integrated Dairy Research, University of Bonn, Bonn 53115, Germany.
Institute of Animal Science, Department of Physiology and Hygiene, University of Bonn, Bonn 53115, Germany.
J Dairy Sci. 2018 Sep;101(9):8417-8428. doi: 10.3168/jds.2018-14500. Epub 2018 Jun 21.
The teat canal is important in the defense against invading pathogens, but its functional features can be impeded by the milking process. The objective of our study was to compare teat morphology before and after a standard milking procedure using high-resolution ultrasonography. Tissue changes were determined by measuring inner traits of teat morphology: teat width, teat end width, teat cistern width, diameter of the lower and upper teat wall, teat canal length, and teat canal diameter. Additionally, 3 traits describing the distal teat canal and its external orifice were established: diameter of the distal teat canal orifice, distal teat canal perimeter, and distal teat canal surface. In the first trial, we verified the repeatability of scanning over time with a mixed model. During the second trial, significant changes after milking were observed for all measured traits of teat morphology except teat end width. The traits from the distal teat canal and its orifice were remarkably changed by milking: distal teat canal orifice, +28.9%; distal teat canal perimeter, +25.0%; and distal teat canal surface, +41.5%. Comparing multiparous versus primiparous cows, higher values of teat width, teat end width, and teat canal length were observed in the older animals. Testing the effect of milk yield on teat dimensions, cows with milk yields >11.0 kg/afternoon milking were found to have larger teat widths, teat end widths, and cistern widths before attachment of the cluster. Furthermore, we observed associations of inner teat morphology toward bacterial counts in the appropriate milk. Regarding this udder health-related parameter especially, the newly established traits showed a connection. Teats in which milk showed bacterial growth had larger distal teat canal perimeters and distal teat canal surfaces. High-resolution ultrasonographic scanning of dairy teats allowed a detailed visualization of the inner morphology. The applied procedure can therefore serve as a useful tool for comparison and evaluation of different milking techniques by analyzing the resulting changes of the morphological traits. The thorough description of teat tissue can also be applied for drawing conclusions on the status of the teat canal's physical and mechanical defense function.
输乳管在抵御入侵病原体方面很重要，但挤奶过程可能会妨碍其功能特性。我们的研究目的是使用高分辨率超声比较标准挤奶程序前后的乳头形态。通过测量乳头形态的内部特征来确定组织变化：乳头宽度、乳头末端宽度、乳池宽度、下乳头壁和上乳头壁直径、输乳管长度和输乳管直径。此外，还建立了描述远端输乳管及其外口的 3 个特征：远端输乳管外口直径、远端输乳管周长和远端输乳管表面。在第一次试验中，我们使用混合模型验证了随时间扫描的可重复性。在第二次试验中，除了乳头末端宽度外，所有测量的乳头形态特征在挤奶后都发生了显著变化。挤奶后，远端输乳管及其外口的特征明显改变：远端输乳管外口直径增加了 28.9%；远端输乳管周长增加了 25.0%；远端输乳管表面增加了 41.5%。比较经产牛和初产牛，年龄较大的动物乳头较宽、乳头末端较宽、输乳管较长。测试产奶量对乳头尺寸的影响，发现下午挤奶量大于 11.0kg 的奶牛在安装牛颈枷前具有更大的乳头宽度、乳头末端宽度和乳池宽度。此外，我们还观察到适当牛奶中的细菌计数与乳头内形态之间的关联。特别是对于这个与乳房健康相关的参数，新建立的特征显示出了关联。牛奶中出现细菌生长的乳头具有更大的远端输乳管周长和远端输乳管表面。奶牛乳头的高分辨率超声扫描允许对内形态进行详细可视化。因此，该应用程序可以通过分析形态特征的变化来作为比较和评估不同挤奶技术的有用工具。乳头组织的详细描述也可以用于得出关于输乳管物理和机械防御功能状态的结论。
