Milking interval, milk production and milk flow-rate in an automatic milking system

One of the characteristics of automatic milking is that cows can visit the milking robot voluntarily. This induces a large variation in the frequency of visits to the milking robot and, thus, results in a large variation in m ilking intervals. The relationships between milking interval, milk producti on and milk flow-rate using a milking robot were studied with data from a r esearch farm (66 cows) collected between October 1997 and September 1999 (1 07 785 milkings). The average milking interval was 9.2 h (S.D. = 3.3). The average milk flow-rate was 2.5 kg/min (S.D. = 0.79) and the average milk pr oduction was 1.3 kg/h. There was a large variation in milking intervals. Re spectively, 9.7 and 17.6 percent of the milkings had an interval shorter th an 6 h or longer than 12 h. In this variation, cow factors do play a role. Of all cows, 6% had an average milking frequency of less than twice per day . Cow factors and time of the day contributed to the variation in milking i nterval. In addition to cow factors, the length of the milking interval had a significant effect on milk production and milk flow-rate. The effects of milking interval on milk production per hour were greater for higher produ cing cows than for lower producing cows. The variation in the milking inter val could be part of the explanation for an apparent increase in SCC with a utomatic milking. Optimisation of the milking frequency and thus the milkin g intervals is important. This optimisation should consider effects of milk ing interval on milk production, capacity of the automatic milking system a nd udder health. (C) 2001 Elsevier Science B.V. All rights reserved.