Blood Groups in the Cat

By Tony Batchelor, Snugglebugs, Denmark.
(Reprinted with permission)

I started this investigation following a blood test on our Devon Rex kitten. She was found to be type B, when both her parents had been tested as type A. I had already been involved with the article by Judith Picknell, and the Danish translation of it, so was aware of the potential problems of mismatched blood types for a mating.

I then looked for and found various articles on the Internet, and have compiled all the data available to me into this document. Initially I just listed the URL's and then extracted the data specifically on the distribution of blood groups. They are shown below in text only form. I have corrected any obvious spelling mistakes.

Although the importance of blood groups is known to breeders, the exact reason does not seem to be appreciated. Obviously, for blood transfusions, correct matching is important, although the difficulty of matching is much less than for humans with the more limited range of blood types. However, the effect of incompatibility between mother and kittens is not at all well known. The risk to kittens in the first few hours after birth can, in some instances, be very high; in fact, in some litters mortality will be 100% if no precautions are taken.

The reasons for this effect of blood groups in cats can be summarised thus:

• Immediately after birth, the surface proteins of the kittens red blood cells may in some circumstances react to antibodies from the mother, and this will destroy the kittens blood cells.
• The circumstances are:
  only if the mother has type B blood,
  and if a particular kitten has type A blood.
• A kitten having type A can only occur if the father is type A (or type A carrying B).
• The kittens obtain the antibodies only after birth, from the first milk, colostrum.

This problem in some matings will affect kitten survival and the population make-up:

• Hardly surprisingly, in the general cat population, as type B mothers will be prone to lose more kittens than type A mothers, the tendency will favour type A.
• However, in geographically closed populations, type B can have the ascendancy.
• Similarly, in selected pedigree populations, particularly where the breeder can feed kittens at risk away from the mother for the first 16-24 hours, type B females have the opportunity to find more type B males.

These tendencies are reflected in the statistics presented in various research papers and research based articles:

• In general, domestic cats ('the general population') have 7-8% type B in the UK but 1% in the USA
• The highest percentages of type B in pedigree cats occur in the British and Rex:
• British have from 40-59% in the USA and 59% in the UK.
• Devon Rex have from 41-45% in the USA and 54% in the UK.
• Cornish Rex have from 33-40% in the USA and from 20-30% in the UK.
• In Turkey, Van were 60% type B and Angora were 46% type B.

The reason for the differences between percentages in the different countries own research is probably statistically insignificant. The significant difference for the Rexes between the two countries is very interesting. The difference between the general cat population ('domestics') and the selected ('pedigree') cat population is highly significant.

Generally, it should be clear to all breeders that the death of just born kittens due to this problem is in the main avoidable by blood typing before mating.

If you wish to look at the statistical detail, I have listed below all the sources that I could find for use in this article. At the end of the listings, I have then made a simplified table to compare the various findings. Each link is active.

Ref. 1
From Journal of Veterinary Medicine Series A
http://cat.inist.fr/?aModele=afficheN&cpsidt=15061437

113 Turkish Van and Angora cats were examined for blood typing using a slide and tube agglutination assay. Of the 85 Van cats surveyed, 40% had type A, and 60% had type B blood. Of the 28 Turkish Angora cats, 53.6% had type A, and 46.4% had type B blood. No type AB cats were found between both breeds. This was in Turkey.

Ref. 2
From Judith Picknell
http://www.rhagorol.co.uk/rexcatz/bloodgroups.htm

The most extensive study to date of feline blood-type distribution across different breeds has been carried out by Professor Giger and his team at the University of Pennsylvania, USA, which shows 33% of Cornish and 45% of Devons are type 'B'.

Ref. 3
From Urs Giger and Margret L. Casal
http://www.rapidvet.com/fading.html

Table 4: Blood type A and B frequency and risk for neonatal isoerythrolysis in the United States

Ref. 4
From DMS Laboratories (associated with Urs Giger) based in the USA
http://www.rapidvet.com/felinepi.html

Ref. 5
From Dr. Diane Addie based in the UK
http://www.dr-addie.com/Blood%20groups.htm#What%20is%20neonatal%20isoerythrolysis?

* Where I have not tested any members of a breed, or another author has tested more cats, I’ve used their percentages: Knottenbelt et al, 1999₁ or Callan & Giger, 1994₂.

Ref. 6
From Urs Giger 1991 USA (my translation) Found at
http://www.felissana.nl/dutch/text/folders/Folder%20Bloedgroepen%2003-2002.pdf

Ref. 7
From Knottenbelt et al 1999 UK (my translation) Was also found at
http://www.felissana.nl/dutch/text/folders/Folder%20Bloedgroepen%2003-2002.pdf

My combined table

For this I have listed only the results for Type B. I have also used the EMS breed codes for simplicity.

Under Breeds, the ¤ shows non-FIFe breeds.

In the original abstracts, no indication is given for some breeds as to whether or not both Long and Short Hair varieties are included.

Under the percentages, the * indicates statistically insignificant results.

NOTE that some references above are different abstracts from the same source, but the comparisons below show/that they report different figures - perhaps the abstracts were put together from/on different dates?

Conclusion

My own personal conclusion from the various documents, as summarised above, is that the British, Devon Rex and Cornish Rex (in that order) breeds are the most at danger of postnatal kitten deaths due to blood type problems. It is clear, assuming the studies were definitely localised by country, that the modern breeders by importing and exporting queens and studs will have in the near future a more pressing need to blood type the cats before mating, if the problem of post-natal kitten deaths due to blood type problems is to be minimised. Additionally, the European policy of reducing the allowed cross-breeding at least in some breeds, is a sensible one from this point of view.

Composite © Tony Batchelor 7th December 2003 Odense