Effect of Teat-End Vacuum Fluctuations on Milking Rate and Mastitis

Abstract

Summary Two groups of eight cows each were milked for 25-day periods with either a regular milking machine or one in which the milk was elevated 6ft before it was returned to the milker pail. The purpose of this experiment was to determine the effect of teat-end vacuum fluctuations resulting from the elevation of milk on the incidence of udder irritation and the rate of milking. At the end of the 25-day period the treatments were reversed and the study was continued for another 25-day period. One group of cows was free from all mastitis organisms, whereas the second group had 12 quarters with persistent mastitis infections. The maximum vacuum fluctuations were measured during the maximum rate of flow and they averaged 2.81 and 3.36 in. Hg for the control and elevated-line milkings, respectively. The cows milked with the elevated line had a significantly longer total milking time, a lower maximum rate of flow, and the vacuum level was lower in comparison to when they were milked with the control machine. No difference was noted in the California Mastitis Test (CMT) ratings or leucocyte counts due to the different milking systems; however, the CMT ratings were significantly higher during the second 25-day period than the first.