The effect of intrauterine and cervical manipulation on the equine oestrous cycle and hormone profiles
Hurtgen, J.P.; Ganjam, V.K.
Journal of Reproduction and Fertility. Supplement 1979(27): 191-197
1979
ISSN/ISBN: 0449-3087 PMID: 289789 Document Number: 139384
Endometrial biopsy or endometrial biopsy and uterine culture taken on 4 days after oestrus induced lysis of the corpus luteum (CL), resulting in a sharp decline in serum progesterone concentration and shortened the interoestrous interval in 8/12 and 32/33 oestrous cycles, respectively, during 2 experiments. Cervical dilatation 4 days after oestrus shortened the interoestrous interval in 5/10 and 0/5 oestrous cycles. Endometrial biopsy and culture on days 1 and 3 after oestrus also induced CL lysis during 4 of 7 cycles. Total oestrogen (oestrone plus oestradiol) concentrations increased at the onset of the subsequent oestrus in mares biopsied on day 4 of dioestrus or in control cycle oestrous periods. Endometrial biopsy also induced lysis of the CL in mares with persistent luteal function. It is postulated that intracervical or intrauterine manipulations during the luteal phase of the oestrous cycle may directly, or indirectly, stimulate the release of an endogenous luteolysin (prostaglandin) resulting in CL regression, followed by oestrus and ovulation in the mare.