Ovulation detection and timing of insemination based on hormone concentrations, vaginal cytology and the endoscopic appearance of the vagina in domestic bitches
Jeffcoate, I.A.; Lindsay, F.E.
Journal of Reproduction and Fertility. Supplement 39: 277-287
1989
ISSN/ISBN: 0449-3087 PMID: 2621729 Document Number: 341722
It was shown that the fertilization period can best be determined using a combination of vaginal cytology and morphology of the vaginal mucosa, behaviour and endocrinology. Neither vaginal cytological changes nor standing oestrus were reliable indicators of the fertilization period per se, although with natural mating or when using AI with fresh semen there may be enough biological leeway for pregnancy to follow insemination timed using these traits alone. This is indicated by the well recognised fecundity of bitches mated early or late in oestrus. Precise discrimination of the fertilization period, which is often required and is necessary for AI using frozen semen, could be achieved using vaginoscopy to detect the onset of shrinkage with angulation of the mucosal folds. Vaginoscopy was also useful to determine the probable end of the fertilization period, and the transition to a metoestrous vaginal smear was also useful in this regard. Detection of the LH peak enabled the start of the fertilization period to be forecast quite precisely but, in lieu of practical assays with which to measure the plasma LH concentration, a rise in plasma progesterone concentration to 6-8 ng/ml may be more practical.