A cat in New Zealand was suspected of eating rat poison. The owner rushed the cat to the vet’s office, but it was too late in the day to match and obtain cat’s blood. Dog’s blood was available at the time and was used to transfuse the cat and save its life.
Cats do not have naturally occurring antibodies against canine red blood cell antigens. However, within 4-7 days after transfusion, antibodies are present. Repeated transfusion with canine blood later than 4-6 days after the first transfusion causes anaphylaxis, often fatal. Anaphylaxis is a very severe form of allergic reaction. Since it is potentially life-threatening, it requires immediate medical treatment.
This means that a dog’s blood transfusion can be used, in an emergency, ONCE, until cat’s blood can be located.