Recovery of cow teats after milking as determined by ultrasonographic scanning.

Recovery time of teat tissue after milking was determined by ultrasonographic scanning. Teat-canal length, teat-end width, teat-wall thickness, and teat-cistern width of 18 cows varying in parity and lactation stage were measured in duplicate before and directly after milking and every hour for 8 h. The ratio between teat-wall thickness and teat-cistern width was calculated. The effects of time after milking and teat position on the teat parameters were estimated using REML models. The mean differences of ultrasound measurements of teat-end width and teat-canal length between duplicate measurements were 3.6 and 8.2%, and between d 4.4 and 7.8%, respectively. Teat-wall thickness and teat-cistern width were more variable (15.3 and 22% between duplicates, and 13.6 and 19.9% between days, respectively). Teat recovery after milking took a considerable amount of time: teat-wall thickness, 6 h; teat-end width, >8 h; teat-canal length, >8 h; teat-cistern width for rear teats, 3 h, and front teat 8 h, and the ratio of teat-wall thickness and teat-cistern width, 6 h. Ultrasonographic scanning of teat parameters was a useful tool to study teat changes caused by milking. Teat recovery took more time than expected, which makes caution necessary when increasing the milking frequency.