ACTA SCIENTIAE VETERINARIAE, vol.47, 2019 (SCI-Expanded)
Background: The mares are seasonally polyestrous animals that regular ovulatory cycles of mares occur together with increasing day length. Exposure of mares to an artificial photoperiod is the most common and predictable technique that it is used to develop follicular activity early in the year. Follicle activity is minimal in mares during two winter months of January and February in Northern Hemisphere. The main objective of this study was to investigate efficacy of artificial lighting and timing of altrenogest treatment for hastening the ovulation in Thoroughbred mares.