Vaginal and cervical mucus ferning as a method of detecting estrus in mares

A two-phase study was conducted to evaluate cervical and vaginal mucus ferning as a method for detecting estrus in mares. The ten mares utilized in Phase A were teased every third day while in diestrus and daily during estrus over a 70 day period. Cervical dilation, cervical mucus ferning and vaginal mucus ferning were monitored following teasing. The correlations between teasing and cervical dilation, cervical mucus ferning, and vaginal mucus ferning were: .44 (P<.01), .35 (P<.01), and .36 (P<.01), respectively. The correlation found between cervical and vaginal mucus ferning was. 48 (P<.01).The six mares in Phase B were given PGF_2α on days 0 and 14, and HCG on days 6 and 20. Cervical dilation, as determined by rectal palpation, and vaginal mucus, taken by suction and swab techniques, were monitored on days 17 through 30 prior to daily teasing. The correlations between teasing and cervical dilation and vaginal mucus ferning, obtained by suction technique, were .11 (P>.05) and .23 (P>.05), respectively. Vaginal mucus samples obtained using the suction method more effectively (P<.01) produced ferning patterns than those obtained using the cotton swab technique. The vaginal mucus ferning technique, however, does not appear as effective for detecting estrus in mares as using a teaser stallion.