Xenotransfusion, a potential life-saving option when compatible feline blood is not available for anemic cats, was examined in this review of 4 studies and 1 case report involving transfusion of canine blood to 62 cats. In most cases, testing before transfusion did not reveal any agglutination or hemolysis of canine RBCs when mixed with feline serum or plasma. Acute severe adverse reactions were not reported in cats receiving a single transfusion of whole canine blood, likely because cats do not appear to have naturally occurring antibodies to canine RBCs. However, within 4–7 days of transfusion, the cats seemed to develop these antibodies, causing delayed hemolytic reaction. Repeat transfusion of canine blood 4–6 days after the first transfusion caused an acute severe reaction, often fatal. Transfused canine RBCs do not last >4 days in feline patients, whereas transfused feline RBCs can last up to 30 days.

A single transfusion of canine blood to a cat can be safe and effective in an emergency, but compatible feline blood is always recommended over canine blood.

Transfusion technology has progressed to wider availability of blood products, but little thought seems to be given to possible alternatives when specific products are unavailable.

At first glance, the title of the study concerned me: I considered xenotransfusion to be ethically wrong with no place in modern veterinary medicine. But, after reading on, I revisited this conviction. Of available blood products, feline RBCs are more difficult to procure, have a short expiration date, and are not commonly stocked by general practices, perhaps because they are relatively expensive. Transport to a specialty practice may not be affordable or feasible for owners. Without an alternative (eg, hemoglobin-based oxygen carrier), a critically anemic feline patient could die from lacking immediate access to feline blood products. Based on this review, it may be time to ruminate on how a single infusion of canine blood into a cat may be life-saving with few long-term consequences.—Elke Rudloff, DVM, DACVECC

Xenotransfusion of canine blood in the feline species: Review of the literature. Bovens C, Gruffyydd-Jones T. J FELINE MED SURG 15:62-67, 2013.