Abstract

The effects of stocking rate (low, L; and high, H), breed (Jersey, J; and Friesian, F) and age (2, 3, >3 years old) on the intervals from calving to first ovulation and to first oestrus were assessed in pasture grazed dairy cattle using a 2 x 2 design. Cows in the FH herd had longer intervals from calving to first postpartum ovulation (C-ovn1; 49.2 vs 24.7, 31.1 and 29.4 days) and C-hl (47.1 vs 32.5 days) intervals than older cows, with 3 year old cows intermediate. The high stocking rate herds had reduced CS, liveweight and milk production compared to the low stocking rate herds. Condition score and milksolids production were inversely related to the C-ovnl and/or C-hl intervals. Increased stocking rates were associated with longer periods of postpartum anoestrum.

S, McDougall, CR Burke, NB Williamson, and KL Macmillan

Proceedings of the New Zealand Society of Animal Production, Volume 55, , 236-238, 1995