Prolonged spring oestrus in mares: The use of progestogens with specific reference to proligestone

The problems of prolonged spring oestrus in mares, which is often associated with multifollicular ovaries (MFO), are described in the context of the need to produce foals early in the year. The results obtained, in terms of pregnancy and time of ovulation, after the intramuscular administration of a single standard 15-ml (1500 mg) dose of proligestonea are described and compared with data available for allyl trenbolone, b, which is given orally, and with accepted data for non-medicated mares. It is concluded that proligestone may be useful in treating MFO and that its use may even aid conception. This latter observation is worthy of further investigation