Changes

===Equine neonatal isoerythrolysis===

===Equine neonatal isoerythrolysis===

In foals, the condition results when a foal inherits red blood cell antigens (which the dam does not have) from its sire. The Aa and Qa antigens are   Exposure of the mare to these antigens during a previous pregnancy or whole blood transfusion leads to the mare producing alloantibodies to the foal's red blood cells. At birth the foal ingests large numbers of red blood cell antibodies in the colostrum, leading to severe haemolytic disease. During pregnancy however, the foal is unaffected because blood and antibodies are unable to cross the placenta. First foals are rarely affected, as a sensitization reaction (during an earlier pregnancy) is usually required.

In foals, the condition results when a foal inherits red blood cell antigens (which the dam does not have) from its sire. The Aa and Qa antigens are most strongly antigenic and exposure of the mare to these antigens during a previous pregnancy or whole blood transfusion leads to the mare producing alloantibodies to the foal's red blood cells. At birth the foal ingests large numbers of red blood cell antibodies in the colostrum, leading to severe haemolytic disease. During pregnancy however, the foal is unaffected because blood and antibodies are unable to cross the placenta. First foals are rarely affected, as a sensitization reaction (usually during an earlier pregnancy) is usually required.

==Clinical signs==

==Clinical signs==