References
- Morris , CA , Day , AM , Amyes , NC and Hurford , AP . 1992 . Ovulation and calving data from a herd selected for twin calving . New Zealand Journal of Agricultural Research , 35 : 379 – 391 .
- Fielden , ED , Macmillan , KL and Watson , JD . 1973 . The anoestrous syndrome in New Zealand dairy cattle. 1. A preliminary investigation . New Zealand Veterinary Journal , 21 : 77 – 81 .
- Macmillan , KL , Day , AM , Taufa , VK , Henderson , HV and Allison , PA . 1987 . Some effects of injecting a prostaglandin F2α (Lutalyse) during the post-partum period on the subsequent fertility of dairy cows . Proceedings of the New Zealand Society of Animal Production , 47 : 65 – 68 .
- Asdell , SA . 1968 . Cattle Fertility and Sterility Boston : Little, Brown & Co., .
- Hafez , ESE and Gordon , I . 1962 . “ Female reproductive organs of farm mammals ” . In Reproduction in Farm Animals Edited by: Hafez , ESE . 79 – 96 . London : Bailliere, Tindall and Cox, .