Ultrasonographic visualization of machine milking induced teat tissue changes in Holstein Friesian × Sahiwal crossbred dairy cows

Sa？etak The study was conducted to observe the internal post-milking teat tissue changes and to evaluate recovery to pre-milking conditions, using ultrasonography. Left-sided teats of Holstein Friesian × Sahiwal crossbred dairy cows (n = 20) were scanned six times: before milking, immediately after milking, and at 1, 2, 3, and 4 hours after milking. Absolute and relative changes of teat canal length (TCL), teat diameter (TD), teat wall thickness (TWT) and teat cistern diameter (TCD) were measured. Machine milking significantly (P<0.001) affected all the measured teat parameters. There was a lengthening of the teat canal (19 - 25%), widening of the TD (19 - 20%), thickening of the teat wall (26 - 36%) and narrowing of TCD (51 - 52%). The time taken for the teats to return to their pre-milking state was significantly affected by teat position. The TWT, TCL and TD were recovered at 3 to 4 hours in the left front teats. In left hind teats, only TWT was recovered at 4 hours of milking. The deviations were highest immediately after milking for TD and TCD, and at 1 h after milking for TCL and TWT. We concluded that the time period of 4 hours is not sufficient for the complete recovery of the teats to the pre-milking state in Holstein Friesian × Sahiwal crossbred dairy cows