Genetic blood group determination

The AB system is the major blood group system in domestic cats. The common blood types are A and B. Cats with blood type B usually have anti-A antibodies at a high titer and cats with blood type A usually have anti-B antibodies at a low titer. Cats with the rare AB blood type (also called blood type C) do not have anti-A or anti-B antibodies (universal receiver).

By the use of a incompatible blood type in a blood transfusion, the natural antibodies lead to blood type incompatibility which could be lethal. First symptoms are dyspnea, vomiting and agitation.

Neonatal isoerythrolysis occurs when a female cat with blood type B is bred to an A-type male cat and the A-type kitten absorb the anti-A antibodies from the breast milk. This hemolytic disease can also be lethal.

Genetic blood type - the variants and inheritance

The genetic determination of the blood types in cats enables the genetic differentiation of the serologically determined blood group before breeding. Blood type A is dominant to B. With the genetic test, it´s possible to identify the recessive b allele which is associated with the B serotype. Cats with two copies of the b allele have the type B. Cats with blood type A can carry the genotype AA or Ab.

To clarify the genetic basis with blood type A or AB the gene test is recommended.