Does omission of a regular milking event affect cow comfort?

摘要

These studies investigate how omission of a scheduled milking event affects indicators of cow comfort. In Study 1, spring calving cows were randomly assigned to one of three milking frequency treatments from calving: twice a day milking (TADAII; n = 14); twice a day, switching to once a day milking at 112 DIM (TAD/OAD; n = 14) and OAD switching to TAD at 112 DIM (OAD/TAD; n = 14). Locomotion ability (ab/aduction, tracking score, speed, head bob, and spine curvature), udder firmness, and milk leakage were assessed weekly for the first 12 weeks of lactation in order to determine initial post-partum differences. Locomotion and udder firmness scores and milk leakage were recorded three mornings prior to, two days immediately after, and one week after the milking frequency switchover. Lying behaviour was recorded for four days using modified voltage dataloggers (Tinytag Plus, Chichester, UK) prior to, during, and after the week of the switch. There was no overall effect of treatment on locomotion scores. TAD/OAD cows showed an increase and OAD/TAD cows a decrease in udder firmness scores on the day after the switch (P<0.05). The likelihood of a cow leaking milk was higher on the day after the switch (P<0.05). OAD/TAD cows spent more time lying than TAD/OAD cows on the day of (P<0.05) and on the day after (P = 0.1) the switch. In study 2, spring calving cows (n = 36) were randomly assigned to three treatments, two of which were used for the study: milked either 14 (14x) or 13 (13x) times weekly. 13x cows were not milked one evening each week. Lying behaviour was recorded on the day prior to, the day of, and the day after the omitted evening milking for 2 consecutive weeks. Udder tension and milk leakage were recorded the morning of the day of and the day after the omitted evening milking for three consecutive weeks. On the day of the omitted milking, 13x tended to have shorter lying bouts than 14x cows (P = 0.1), and tended to spend less time lying/hour than 14x cows, particularly 13 to 24 hours post milking (P = 0.06). On the day after, 13x cows had higher udder tension scores (P<0.001), and a higher incidence of milk leakage (P<0.001) prior to milking than 14x cows. In both studies changes in behaviour and udder tension were transient. Thus the practice of reducing milking frequency from twice to once daily in mid lactation, or omission of a weekly milking event, is unlikely to be a significant welfare problem for dairy COWS