Clinical and endocrine studies during normal and induced parturition in mares

Parturition was induced in 6 mares between Day 327 and 346 of pregnancy using oxytocin (Group I) and in 6 mares between Day 315 and 330 of pregnancy with fluprostenol in combination with oxytocin (Group II). A third group of 4 mares which served as controls were allowed to go to full term (322-340 days) and foal down normally. Parturition occurred within 24-102 min (mean = 61,4; SD = 31,6) in 5 of the Group I mares and within 160-185 min (mean = 173; SD = 10,86) in the mares of Group II. Expulsion of the afterbirth took place between 7 and 206 min (mean = 79; SD = 76,38) and between 7 and 73 min (mean = 37,5; SD = 21,29) in Groups I and II respectively. Three of 6 mares in the oxytocin group showed foal heat, all 3 conceived and 2 carried foals to term. Of the remaining 3 mares, 2 showed heat approximately one month after parturition, and were served and conceived but one aborted due to babsesiosis and one resorbed while the third remained in anoestrus for 3-4 months. In the combined treatment group, 3 mares showed foal heat of which only 2 were served. Both conceived and one carried a foal to term. One of the remaining mares showed oestrus 2 months after parturition while the remaining 2 mares showed oestrus approximately one month after parturition. Both were served, one conceived but subsequently resorbed.(ABSTRACT TRUNCATED AT 250 WORDS)