Two related cases of cerebellar abnormality in equine fetuses associated with hydrops of fetal membranes.

Hydrops allantois was diagnosed in two Haflinger mares with severe abdominal distension. Both mares were seven months pregnant. Abortion was induced with two injections of prostaglandin six hours apart followed by further manual dilation of the cervix and administration of oxytocin the next day. There were 90 and 95 litres of fluid, respectively, in the allantoic cavities which resembled extracellular fluid with regard to concentrations of urea, creatinine, sodium, potassium, calcium, magnesium, phosphate and chloride, but not total protein. Both fetuses had severe brain abnormalities which were diagnosed as cerebellar and cerebral hypoplasia associated with bilateral hydrocephalus internus and hydranencephaly and cerebellar aplasia, respectively. Both mares were pregnant by the same stallion, but a clear hereditary link was not found.