− | The number of blood groups varies between the domestic species and are determined by the presence of antigenic components on the surface of the [[Erythrocytes|red blood cells]]. Cattle have 2 blood groups (B and J) and the most complex blood group systems while cats have 3 blood groups and are quite simple. Dogs have 8 blood groups, Horses have 3, A, C and Q and sheep have 2 groups B and R. | + | The number of blood groups varies between the domestic species and are determined by the presence of antigenic components on the surface of the [[Erythrocytes|red blood cells]]. Cattle have 2 blood groups (B and J) and the most complex blood group systems while [[Blood Groups - Cat|cats have 3 blood groups]] and are quite simple. [[ Blood Groups - Dog|Dogs have 8 blood groups]], Horses have 3, A, C and Q and sheep have 2 groups B and R. |