Lely Industries NV, Weverskade 110, NL-3147 PA Maassluis, the Netherlands.
J Dairy Sci. 2010 Jan;93(1):45-52. doi: 10.3168/jds.2008-1864.
During milking, the teat is loaded because of a combination of vacuum and pressure of the collapsing liner. It is assumed that pressure concentrations tend to cause teat-end injuries and hyperkeratosis. The pressure distribution on the bovine teat was measured to test the hypothesis that the pressures of the collapsed liner are unevenly distributed over the teat. With the aid of a pressure-sensitive sensor (approximately 2 gauge points/cm(2)), the pressures at the teat-liner and the teat-calf interfaces were measured at 100 Hz. Pressure distribution over the surface of an artificial teat was measured with 7 different liners, 1 liner at 3 different vacuum levels, and a suckling calf. One cow was equipped with a sensor at a teat during a milking with one of the liners. Conventional round liners concentrated the load over 2 sites at the teat end. Some liners (softer material, reduced tension, smaller barrel, reduced mouthpiece depth) distributed the compressive load over a larger area of the teat. Although all liners distributed the highest pressures at the teat end, some liner designs showed a 25% reduction at the site of interest at vacuum of 44 kPa. The calf forced milk flow by a combination of suckling and overpressure in the teat cistern caused by the tongue. While the calf was swallowing, teat pressure was reduced because of a decrease in vacuum. Moreover, the calf did not load the teat end, probably because the teat canal would be closed and the milk would not flow. The method of using a pressure sensor to analyze teat loading at the teat-liner and the teat-calf interfaces showed potential and is a first step toward developing a natural milking technique.
在挤奶过程中，由于衬里的塌陷产生的真空和压力的结合，乳头被加载。据推测，压力集中往往会导致乳头末端受伤和过度角化。测量牛乳头的压力分布，以验证衬里塌陷产生的压力在乳头表面不均匀分布的假设。借助压力敏感传感器（约每平方厘米 2 个测量点），以 100Hz 的频率测量乳头衬里和乳头-犊牛界面的压力。用 7 种不同的衬里、3 种不同的真空度和一只吮吸小牛测量人工乳头表面的压力分布。一头牛在一次挤奶过程中用其中一种衬里在一个乳头上安装了传感器。传统的圆形衬里将负荷集中在乳头末端的 2 个部位。一些衬里（较软的材料、张力降低、较小的桶、较小的奶嘴深度）将压缩负荷分布在乳头的较大区域。尽管所有衬里都在乳头末端分布了最高的压力，但一些衬里设计在 44kPa 的真空度下，在感兴趣的部位降低了 25%的压力。小牛通过吮吸和舌头引起的乳头水箱中的过压来迫使牛奶流动。当小牛吞咽时，由于真空度降低，乳头压力降低。此外，小牛不会给乳头末端加载，可能是因为乳头通道会关闭，牛奶不会流动。使用压力传感器分析乳头衬里和乳头-犊牛界面的乳头加载的方法显示出了潜力，是朝着开发自然挤奶技术迈出的第一步。
