Three times a day milking: effects on milk production, reproductive efficiency, and udder health.

Dairy Herd Improvement records from 14 Holstein herds in San Joaquin County, CA were studied. Seven herds were milked three times a day, the other 7 twice a day. Three times daily milking significantly increased yield of 305-d fat-corrected milk. Percentage increases in production were 19.4, 13.5, 11.7, and 13.4% for cows in parity one, two, three, and four or later, respectively. Percentage of milk fat was slightly lower for cows milked three times a day compared with those milked twice a day. Cows milked three times a day had fewer days to first breeding than their twice daily counterparts. First lactation cows milked three times daily had more days to last breeding, more breedings, and consequently, more days open than cows milked twice a day. For second lactation cows milked three times a day, there was no difference in days to last breeding or days open, but they required more breedings than cows milked twice a day. Third and fourth lactation cows milked three times daily had fewer days to last breeding, no difference in number of breedings, and therefore, fewer days open than those milked twice daily. Udder health was evaluated by California Mastitis Test scores. Cows milked three times a day up to their third lactation had higher scores than those milked twice a day. Fourth and later lactation cows had a lower score than cows milked twice a day.