Clients & Visitors

Equine Blood Donors


Mac, Jerry, and Marcus provide blood to their equine friends for life-saving transfusions.

The EMC maintains a small herd of equine blood donors who have collectively donated more than 1,000 liters of blood in critical care situations. These horses live on our property and are well cared for by our faculty and staff.

Blood transfusion is a potentially life-saving procedure for horses suffering from hemorrhagic shock resulting from trauma, laceration, or hemolytic crisis. There is no substitute for whole blood in these circumstances. Whole blood replaces the lost red blood cells and provides protein, clotting factors, and platelets. Horses have a large, contractile spleen, so fairly large volumes of blood can be removed from healthy donors with no negative consequences. The procedure is simple and straightforward, requiring only the placement of a jugular catheter.

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Meet our Blood Donors

Our boys live in a 20-acre field and are well spoiled to ensure that they come when called anytime of the day or night. They have many human friends and receive the best possible veterinary care.

Jerry Jerry, a grey Percheron gelding weighing 1,980 pounds, has been a blood donor since 1997. Before coming to the EMC, he was a driving show horse and also worked at an Amish farm. In 14 years of service as a blood donor, Jerry has donated more than 550 liters of blood. Jerry entertains visitors during open houses and has been used in teaching demonstrations for veterinary students.

Mac Mac, a Belgian Draft cross gelding, came to the EMC in 2004. In seven years of service, he has donated more than 200 liters of blood. Before coming to the EMC, he was a field hunter. He has since put on a few pounds and now weighs more than 2,000 pounds, making him better suited for work that keeps his feet on the ground.

Rabo Rabo, a black Percheron gelding born in 1993, was donated to the EMC in 2010 by the US Army. He served in their Caisson Unit for several years until his retirement in 2010. He has donated 27 liters of blood to date. He is our newest addition and fits in very well with the other boys.

Marcus Marcus (1978-2011) was donated to the EMC by the US Army in 1998, after he had retired from service in their Caisson Unit. He participated in parades and ceremonial activities in the Army for more than 14 years. He lived at the EMC for 13 years until his death in 2011. He was in such good health when he arrived that we thought he was a youngster, but a veterinarian estimated that he was at least 20 years old. In ten years of service as a blood donor, Marcus donated more than 230 liters of blood for a total of 39 transfusions.

Blood transfusions

  • Patients that commonly require tranfusions are those with hemorrhage into the abdomen from a foaling-related tear or a fall or kick. Those bleeds often cannot be repaired by surgery, so supportive care and transfusions are the most common treatment.
  • Patients with red maple leaf toxicity, lacerations with substantial blood loss, anemia, or clotting disorders may also require transfusions.
  • As with humans, horses have multiple blood types. Prior to every transfusion, Mac, Jerry, and Rabo are cross-matched with patients to ensure that their blood does not react adversely with patients' blood.
  • Our blood donors are routinely examined to make sure they are healthy. Their blood is collected as needed, but not more than once per month.