Can I firstly say that I do not have any formal veterinary qualifications and that this article is formed from my own experieces from reading many different publications and listening to people far more knowledgeable than myself.


I first came across Blood Group Incompatibility (BGI) in December 1997, when I bred our Blue boy to our Cream girl. When the resulting kittens were born they were five lovely, big, vigorous kittens. Within 48 hours they were all dead, due to BGI. I noticed within a few hours of the birth all was not well, and my vet referred me to the University Of Glasgow Veterinary School, where they diagnosed BGI. The kittens were taken away from the mother to be hand fed at the school but the damage had already been done, it was a very horrible thing to witness ! Before this incident I had not heard of this condition.


There are two main blood groups in cats - A and b.

Most breeds of cats are of the A blood group but there are a few breeds that have a 50/50 distribution of both groups. These are British Shorthairs, Devon Rex and Exotics. There has been further study and it has now been discovered that 59% of British in the UK have the b Blood Group.


Group A has a dominant inheritance over b. However Group b cats possess very effective antibodies against the red corpuscles of Group A. Therefore when a b queen is mated to an A stud, the litter will be group A - they will be born healthy but when they take and ingest the first milk (colostrum) and therefore the antibodies of their mother, this will destroy their red corpuscles, which leads to death.

BGI may have gone unnoticed by many breeders:

1. Have you ever had queens that never seem to get into kitten, no matter how many matings they have had?

2. Queens that you are convinced are in kitten and then come into call again at 5-6 weeks.

3. A litter of kittens that have been a bit sickly since birth and, at 1-2 weeks old, the tips of their tails die and fall off.

4. Whole litters die for no apparent reason ("Fading Kittens Syndrome").

Any of these circumstances could be attributable to BGI.


What can we do to prevent it?

Essentially, avoid mating the wrong groups together and have all breeding stock grouped.

Owners of stud cats at public stud are providing a chargeable service, therefore to prevent any unnecessary anguish and expense which could accrue, I feel that these people have a moral obligation to have their stud blood grouped.

Once the blood groups of two cats have been identified, the following circumstances should be followed for a successful mating:

1. Group b males can be bred to Group A and b females, without exception.

2. Group A males can only be mated to Group A females.

3. Group b females can only be mated to Group b males.

4. Group A females can be mated, without exception to Group A and b males.


Obviously, when A/b matings of 1 and 4 above have taken place the resultant kittens will be Group A but carrying b as recessive. Therefore cats that are A/b, when mated together, can produce b kittens, hence the reason why kittens kept for breeding programmes should always be blood grouped.


Tests for blood group can now be done by taking a buccal swab from the cats cheek. for more information see

www.catgenetics.co.uk  or www.vgl.ucdavis.edu


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