There can be few events as distressing for a cat breeder as watching a litter of kittens fade and die within the first 48 hours of life. Yet this has been the experience of many breeders until it was recognised that the reason was that the queen had a different blood type from her kittens and was killing them, unintentionally, when they suckled her milk. It is particularly a problem in the British Shorthair, Rex, and Turkish Van breeds as almost 60% are blood group B, but it can affect almost any breed of cat, including the dear old domestic moggy.
Knowing your cat’s blood group can save their and their kittens’ lives.
[This page is written for cat lovers, veterinary students, and veterinary nurses. I apologise to veterinarians for the lack of interesting technical detail, and highly recommend the excellent review by Bighignoli et al in John August's textbook Consultations in Feline Internal Medicine, Volume 6.]
are feline blood groups or blood types?
As you know, if you have a blood transfusion, it is essential to get the right type of blood, a transfusion of the wrong blood type could kill you – it is no different for cats. The immune system of the cat or person receiving the blood transfusion reacts to the blood which it sees as alien, and the consequences can be fatal.
is neonatal isoerythrolysis?
Samples of blood from the kittens and queen can be blood typed to confirm the diagnosis.
1. Typing the queen and tom before mating
Table 1 - What happens when you mate a blood group B queen to a blood group A tom cat depends on whether his genes are purely A or a mixture of A and B. The kitten’s genes are represented by the shaded boxes. The biggest risk of neonatal isoerythrolysis is when kittens with blood type A are born to blood type B queens.
Table 2. - What happens when you mate two blood group B cats together.
All of the kittens will be blood group B (shaded area represents kittens of such a mating) and there will be no risk of neonatal isoerythrolysis.
Table 3. - What happens when you mate two cats with blood type A together.
In the first example above, the tom has both versions of his gene (i.e. the one from his mother and the one from his father) coding for blood group A, therefore all his kittens will be blood type A. Half of his kittens will carry the gene for blood group B, which they have gotten from their queen. None of the kittens will be at risk of neonatal isoerythrolysis as they all have the same blood group as their queen.
In the second table both blood group A cats are carriers of the gene for blood group B. As you can see, one quarter of the kittens born to this pair will be blood group B (shaded box). Queens with blood group A have less anti-type B antibody than blood group B queens have anti-group A antibody, so the type B kittens of this mating might survive. However, if the mating is repeated, the queen will build up anti-B antibody and eventually one fourth of her kittens could die of neonatal isoerythrolysis.
The only way to establish the genotype of a blood type A cat is by trial mating with a type B cat or by submitting a DNA sample to a specialised veterinary laboratory which can genotype cats' blood groups.
Table 4.- The outcome of trial matings to establish whether a blood group A tom carries blood group B genes.
Does Neonatal Isoerythrolysis occur in my breed?
Remember that some breeds are relatively uncommon and not many cats have yet been tested, so that the figures given in this table are based on a small sample size and may not be wholly accurate. If you have had any kitten deaths which could be due to neonatal isoerythrolysis, have your queen tested no matter what breed she is.
Table 6. Blood type B frequencies in various feline breeds: breeds without type B cats are safe from developing neonatal isoerythrolysis.
These figures are mainly based on Bighignoli et al, 2010, and from a study by myself, while at the University of Glasgow Veterinary Diagnostic Laboratory (my own figures are [in square brackets]), that of Knottenbelt et al, 1991 (marked with a K) and that of Callan & Giger (marked CG).
2. Blood group testing the kittens at birth
Prevent at-risk kittens from suckling their queens for 16 hours
There are two options when you decide to establish the blood group of a cat:
1. You can test the cat's blood to establish the group (by submitting an EDTA sample to a veterinary laboratory or using a blood typing in-house card test.)
1. Blood typing card
The advantages of using a blood typing card is that you determine the actual blood group of the cat and it is rapid - can be performed in a matter of minutes. This test is ideal when you are performing a blood transfusion, or typing a newly-born kitten to know whether it's safe to allow him to suckle his queen. The cards tell you whether the cat's blood group is A, B or AB (though a word of caution - Barrs et al found that 16 of 60 cats with blood group A seemed to falsely read blood group AB on the card system because of microscopic rouleaux formation which only disappeared in 4 samples by diluting the sample in saline). The card I use is the RapidVet-H test made by the Italian company Agrolabo. The slight drawback of the card system is that if the cat is blood group A, you cannot determine whether or not he or she is a carrier of the B gene (i.e. Ab). Obviously if the cat is blood group B, you know that genetically he is bb.
You can also send an EDTA sample to Veterinary Diagnostic Services at the University of Glasgow Veterinary School, Scotland, for blood typing.
There is also an immunochromatographic blood typing in-house test called RapidVet-H IC Feline.
At time of writing, tests have to be sent off to a specialised laboratory to determine the genetic blood type of a cat. The advantages of this test are that no blood sample has to be taken - a cheek swab suffices - and it can be used to determine whether a blood group A cat is a carrier of the b gene (and thus risks producing blood group B kittens). A disadvantage is that this test does not discriminate between a cat with blood group A and those with the rare AB group.
This is a film of a buccal swab being taken:
Bighignoli B, Owen SD, Froenicke L, Lyons LA. 2010 In: Consultations in Feline Internal Medicine Vol 6. Editor: August J. Saunders Elsevier, 3251 Riverport Lane, St. Louis, MO 63043 628-638 (This book is available from Amazon and other booksellers.)
Bighignoli B, Niini T, Grahn RA, Pedersen NC, Millon LV, Polli M, Longeri M, Lyons LA. 2007 Cytidine monophospho-N-acetylneuraminic acid hydroxylase (CMAH) mutations associated with the domestic cat AB blood group. BMC Genet. 6;8:27.
Barrs VR, Giger U, Wilson B, Chan CT, Lingard AE, Tran L, Seng A, Canfield PJ, Beatty JA. 2009 Erythrocytic pyruvate kinase deficiency and AB blood types in Australian Abyssinian and Somali cats. Aust Vet J. 87(1):39-44.
Callan, MB, Giger U. 1994 Transfusion medicine. Consultations in feline medicine 2. Ed. August, JR. 525-532
Casal ML, Giger U. 1997 Colostrum: friend or foe? Feline Advisory Bureau Journal 35 70-72
Gurkan M, Arikan S, Ozaytekin E, Dodurka T. 2005 Titres of alloantibodies against A and B blood types in non-pedigree domestic cats in Turkey: assessing the transfusion reaction risk. J Feline Med Surg. 7(5):301-5.
Knottenbelt CM,Addie DD, Jay MJ, Mackin AJ. 1999 Determination of the prevalence of feline blood types in the UK. Journal of Small Animal Practice 40 115-118
Updated 13 July 2012
Site ©2000 - 2012