Lacy-Hulbert S J, Hillerton J E, Woolford M W
Dairying Research Corporation Ltd, Ruakura, Hamilton, New Zealand.
J Dairy Res. 1996 Nov;63(4):517-24. doi: 10.1017/s0022029900032052.
In two separate experiments, the effects of pulsationless milking and milking vacuum on the rate of keratin removal from the teat canal were determined. Sixteen cows were milked with or without pulsation for either a single milking or for eight milkings. Milking without pulsation removed 10% of keratin present before milking, significantly less than milking with pulsation, which removed 32%. After eight milkings (4 d) without pulsation, up to 20% more keratin had accumulated within the teat canal but the rate of keratin regeneration reduced significantly upon return to pulsation milking. In a second experiment, ten cows were milked at 45 or 55 kPa and without pulsation. Only the absence of pulsation significantly reduced keratin loss during milking. Keratin loss during milking appears to be controlled by liner compression rather than by the rate of milk flowing through the teat canal. Pulsationless milking may increase penetrability of the teat canal to bacteria by reducing the natural rate of keratin removal during milking and reducing the rate of keratin regeneration.
在两项独立实验中，测定了无脉动挤奶和挤奶真空度对从乳头管去除角蛋白速率的影响。16头奶牛分别在有脉动或无脉动的情况下进行单次挤奶或八次挤奶。无脉动挤奶去除了挤奶前存在的10%的角蛋白，明显少于有脉动挤奶，后者去除了32%。在无脉动进行八次挤奶（4天）后，乳头管内积累的角蛋白增加了20%，但恢复到有脉动挤奶时，角蛋白再生速率显著降低。在第二项实验中，10头奶牛在45或55千帕且无脉动的情况下挤奶。只有无脉动显著降低了挤奶期间的角蛋白损失。挤奶期间的角蛋白损失似乎受内衬压力控制，而非流经乳头管的牛奶流速控制。无脉动挤奶可能通过降低挤奶期间角蛋白的自然去除率和角蛋白再生速率，增加乳头管对细菌的渗透性。
