Abstract

Multiparous Holstein-Friesian cows (n = 120), grazing pasture and milked twice-daily (2X) from calving until ~35 days in milk, were allocated to one of four treatments. Treatments consisted of 2X or once-daily milking (1X), and UnRes (15 kg dry matter (DM)/cow/day) or Res (9 kg DM/cow/day) pasture intake for three weeks. Following treatment, all animals were milked 2X and offered pasture (residuals of 1,600kg DM/hectare) for 20 weeks. During the treatment period (Weeks 1-3), yields of milk, fat, protein and lactose decreased with reduced milking frequency and feeding level. Interactions existed for milk, protein and lactose yields and the decrease due to 1X milking was greater in the UnRes than Res cows. During the post-treatment periods (Weeks 4-12 and Weeks 13-23) no interactions were present. Restricted cows produced less milk, fat, protein and lactose compared with UnRes cows during Weeks 4-12, but no difference existed during Weeks 13-23. During Weeks 4-12, cows milked 1X produced less milk, fat, protein and lactose than those milked 2X and these differences remained during Weeks 13-23. During the treatment period, body condition score was less in Res than UnRes cows, however there was no effect of milking frequency on body condition score. Neither feeding level nor milking frequency altered post-partum anoestrus interval.

JK, Kay, CVC Phyn, AG Rius, SR Morgan, TM Grala, and JR Roche

Proceedings of the New Zealand Society of Animal Production, Volume 71, Invercargill, 37-41, 2011