Liner overpressure and teat dimensions: preliminary results of a field study

The primary objective of this study was to measure the overpressure (OP) of a liner and assess the relationship between OP and teat dimensions (length and diameter) using a new test device designed to make faster and more accurate OP measurements. The secondary objective was to evaluate the relationship between mouthpiece chamber (MPC) depth and teat-barrel congestion in dairy cows.OP was measured at 1 min and 3 min after the cluster attachment. Teat length and diameter were measured before milking. Teat-barrel congestion was assessed by observing changes in the color of teat skin within 1 min of milking unit removal. The OP value at 1 min after the cluster attachment was 9.7 kPa and a significantly decrease of about 2.7 kPa in OP values were recorded at 1 and 3 min from the beginning of the milking. A positive significant correlation was found between teat lengths and OP values and between teat-barrel diameter and OP values measured at 1 min after the milking unit attachment, but not at 3 min of milking. About 80 % of teats were reddened (congested) or tinged with blue (cyanotic). These results suggest the opportunity to perform OP measurement at a standard time after the cluster attachment to make the measurement values comparable and highlight the importance of a good fit between liner and teat.