Abstract

The successful implementation of automatic milking (AM) technology in pastoral dairy systems is dependent on the regular voluntary passage of cows from the grazing area to the dairy. A herd of 94 cows at the Dexcel Greenfield research farm was observed during a 31-day period to determine the effect of stage of lactation on milking performance and behaviour. Sixty-five cows were spring calved (late lactation, average 266 days in milk) and 29 were autumn calved (early lactation, average 19 days in milk). Cows were grazed as one herd in a rotational grazing management system with a fresh area of pasture available twice daily. Early lactation cows had a shorter average milking interval (14.6 vs 20.4 hours, p < 0.001) and a higher average daily production (20.0 vs 7.0 kg milk/cow/day, p < 0.001). They visited the selection units (from which they could gain access to water, fresh pasture and the raceway to the dairy housing the AM units) more often than cows late in lactation (2.8 vs 1.8 visits/cow/day, p < 0.001) and had a quicker transit time between pasture and the AM units (2.2 vs 2.7 hours/cow/milking, p = 0.026). Fewer early lactation cows needed to be manually moved from the grazing area for milking. The data indicates that stage of lactation will be a significant factor to consider when developing management systems for combining grazing with automatic milking.

JG, Jago, KL Davis, and MW Woolford

Proceedings of the New Zealand Society of Animal Production, Volume 66, Napier, 258-262, 2006