Natural Immunization in Pregnant Goats Against Red Blood Ells of their Sheep X Goat Hybrid Foetuses

Abstract

Female goats readily conceived when mated with male sheep but the foetuses usually died within 2 months. Examination ofliving hybrid foetuses about 2 months old suggested that death was due to haemolytic disease. Haemolytic antibodies against red blood cells of the sire usually appeared in the maternal goat sera shortly after the time of cotyledonary attachment at about 30 days gestation.