The preovulatory follicle in oestrous cycling Angus cow was larger (P<0.01) and contained more granulosa cells (P<0.01) in May and June than in October. Also in May and June, the corpora lutea were heavier (P<0.05) and secreted more progesterone (P<0.01) than in October. In contrast, the luteinizing hormone peak frequency and plasma prolactin concentrations were higher (P<0.01) in October than in May and June. Seasonal differences in ovarian activity are probably a direct consequence of seasonal differences in pituitary gonadotrophin secretion.

HR, Tervit, PG Goold, RW James, and MD Fraser

Proceedings of the New Zealand Society of Animal Production, Volume 44, , 11-14, 1984
Download Full PDF BibTEX Citation Endnote Citation Search the Proceedings

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.