Dropsy of the fetal sacs in mares: induced and spontaneous abortion.

Eight cases of severe dropsy of the fetal sacs have been observed in mares. All were in multiparous mares whose ages ranged from five to 20 years and who were 7 1/2 to 10 3/4 months pregnant. Abortion started spontaneously in four cases and had to be induced in the remaining four by manual dilation of the cervix, rupture of the tough allantochorion and the siphoning off of 120 to 220 litres of allantoic fluid. The amnion was normal. Dystocia, due to uterine inertia, occurred in all eight cases, one hydrocephalic fetus needing fetotomy. All fetuses were alive at delivery although four were teratologically deformed and two were markedly underdeveloped. None survived. Retention of a somewhat oedematous placenta occurred in six cases. Microscopic examination of the placenta showed some evidence of degeneration, but none of inflammatory change. One mare died, seven recovered rapidly. One mare was served again and gave birth to a living foal. Special care needs to be given to pre- and post-operative shock, retained placenta and delayed involution.