CHAPTER 48 Blood-Donor Horses and Whole-Blood Transfusion in Private Practice
Many medical conditions are encountered in equine practice that may lead to the need for lifesaving whole-blood transfusion. Blood loss from traumatic wounds, internal hemorrhage (such as from uterine artery or splenic rupture), or immune-mediated conditions (such as hemolytic anemia, thrombocytopenia, and neonatal isoerythrolysis) can be severe and may necessitate blood transfusion. The ability to provide a critically ill horse with fresh whole blood can potentially save a horse’s life and enhance a practice’s ability to serve its clients.
EQUINE BLOOD TYPES
Alloantigens are antigens that induce an immune response within the same species, and alloantibodies are antibodies produced in response to exposure to an alloantigen. Thirty-two RBC alloantigens in eight major blood groups (A, C, D, D, K, P, Q, and U) have been identified in horses. This accounts for approximately 400,000 possible equine blood phenotypes. These numbers reveal that identifying a perfect blood donor for any one recipient is nearly impossible. Fortunately, there are essentially no naturally occurring alloantibodies against the various equine blood types. The Aa and Qa equine blood types are considered the most antigenic of all the blood types; therefore, Aa /Qa negative individuals are considered universal blood donors. Several laboratories that provide equine blood typing services are listed in Box 48-1.
