Concentrations of luteinising hormone and progesterone in pregnant and non-pregnant heifers
Roche, J.F.; Ireland, J.J.; Boland, M.P.; McGeady, T.M.
Veterinary Record 116(6): 153-155
1985
ISSN/ISBN: 0042-4900 PMID: 3984186 Document Number: 259746
Blood samples were taken from 48 heifers three times a day during a week before and 20 days after AI. Blood progesterone and LH remained constant for up to 16 days after insemination, whether the heifer was pregnant or not, but between 17 and 20 days the progesterone decreased in non-pregnant heifers. Transfer of an embryo to non-pregnant heifers on the 10th or 12th day did not affect progesterone concentration, but the flushing out of an embryo was followed by a fall in progesterone.