Neonatal alloimmune thrombocytopenia, purpura, and anemia in 6 neonatal piglets.

A hemorrhagic diathesis due to neonatal alloimmune thrombocytopenia occurred in a sow herd consisting of F I large white X Landrace females. Colostrum, containing maternal antibodies incompatible with platelet antigens inherited from the sire, was ingested and absorbed by the piglets. Six piglets were affected and displayed signs of lethargy and depression with petechiation, ecchymosis, and severe bruising of the skin. All 6 piglets died or were euthanized by 3 days of age.