[Neonatal hemolytic icterus in foals. A study of antibodies in colostrum and serum]

Investigations for the presence of antibodies to red blood cell antigens were carried out in equine colostrum and serum. Material from 181 mares without clinical disease was tested. The object was to obtain information on the number of mares producing antibodies capable of inducing haemolytic disease in newborn foals. Of the mares 2.8% was positive for haemolysins. These mares are expected to be a risk for haemolytic disease. In addition agglutinating antibodies were identified in 39.2 per cent of the mares examined. It is not known whether or not these antibodies constitute a hazard for the foals. A smaller group of sera from mares was analysed to verify or disprove the diagnosis of haemolytic disease. Some of these mares showed very high haemolysin titres. Several cases are reported in greater detail. It is clear that the information obtained from these cases shows that haemolytic disease of newborn foals also occurs after the first pregnancy of mares.