[Twin pregnancy in mares].

A number of findings on twin pregnancies in mares recently reported in the literature are evaluated in the present paper. From these findings it emerges that twin pregnancies in mares very rarely develop from a synchronous (less than 2 days apart) double ovulation but rather from an asynchronous (much greater than 2 days apart) double ovulation. The significance of these findings in daily practice is pointed out. Moreover, it was found that in more than 50 per cent of the cases in which twin pregnancies had been diagnosed about day 20, one embryo had died by day 36. From this fact it is concluded that twin pregnancies in which an early diagnosis is established, should not be interrupted too soon. The would seem to hold good particularly for those cases in which a diagnosis of twin pregnancy was established by ultrasonic echography as early as day 14.