Below is an article I wrote on Blood Type.
An adapted version (from my original) was also published in the April/May 2009 Sphynx Newsletter.
The
Importance of Blood Type in Sphynx
By Emily Greene
Special thanks to Dr. Melba Ketchum
of DNA Diagnostics for her time and assistance in compiling the data for this
article.
Abstract: This is the first time quantified data for the Sphynx breed with both blood alleles has been compiled for breeder use. The Sphynx population does have a high percentage of B blood type, and even higher percentage of Sphynx carrying B blood type and therefore blood typing is highly advisable. Sphynx are the first breed to have results compiled with the alleles, so there are no other breeds to compare to at this time.
---------------------------------------------------------------------------------------------------------------------
As a breeder you may ask yourself,
“What is blood type, why
is it important to know about blood type and is it relevant in the Sphynx breed?
“
Blood type is a classification for some of the proteins (antigens) found in the red blood cells. Blood typing is important because blood type incompatibility can have serious affects, even death, in newborn kittens and the rare case of a blood transfusion.
In felines, there are 3 different blood types: A, B, and the extremely rare AB. Different animals have different numbers of blood types. To give some perspective, dogs have 13 different blood types and humans have four. Each feline breed and country has a different frequency of B blood type.
In felines, A blood type is dominant over B. An A blood type cat can be A/A or A carrying B since it is dominant. Since the B blood type is recessive, a B blood type cat both alleles must be B. Rarely, there are cats that are AB blood type and they should be treated like the blood type A cats when dealing with kittens and blood transfusions.
Blood group B cats have naturally occurring anti-A antibodies in their blood. Basically the B cells will always attack the A blood cells. Anytime this occurs, there can be a fatal reaction.
If a B blood type cat is given a blood transfusion from an A blood type cat, the transfused cells from the A cat will be destroyed and a potentially fatal reaction will occur.
Antibodies in the blood are in the colostrum and milk, so if a newborn blood
type A kitten nurses from a blood type B queen during its first few days of
life, it may absorb large amounts of anti-A antibodies, causing damage to its
type A red blood cells. This is called neonatal isoerythrolysis.
This severity of the reaction varies by
kitten. Some of the signs in kittens that have died from blood type
incompatibility are jaundice, anemia, bloody urine. Some mildly affected kittens
do live but have the tip of their tail or ears fall off.
The DNA Blood
Allele Results
For the very first time in Sphynx, DNA results with both alleles have been compiled by Dr. Melba Ketchum of DNA Diagnostics. They have tested over several hundred Sphynx and proper sampling techniques were used. The results are in the chart below:
|
Blood Type |
Alleles |
Sphynx Population |
TOTAL % Blood Group |
|
A |
A/A |
46.4% |
|
|
A |
A/B |
37.7% |
A=84.1% |
|
B |
B/B |
15.9% |
B=15.9% |
A high number of Sphynx are “B” blood type. There is quite a high number of Sphynx that are carrying “B” blood type. It is recommended that all Sphynx in breeding programs get blood typed.
The elimination of the “B” blood type is possible now with the advent of the DNA testing.
“What if my cat tests “B”?” It is important to differentiate if it is a male or a female.
If female, it is a little bit tricky. Many breeders will opt to eliminate this queen from the breeding program. Another option is she can be bred to a B blood type male with no blood compatibility issues. This does not eliminate the B blood type from the Sphynx breed however. If she is bred to an “A” type male, all kittens will need to be hand fed for the first 72 hours of its life to prevent neonatal isoerythrolsis. (Note: The amount of time recommended for handfeeding before it is safe to place the kittens back on the mom varies by individual kitten, but 72 hours is the safest.) It is important to note that not only is it a lot of hard work for the breeder, but the kittens miss out on the colostrum that is naturally found in the mother’s milk. Colostrum is so important for their immunity.
If you do have a newborn that gets NI, you can save try to save the kitten’s
life by giving it a blood transfusion from the dam.
Dr. Ketchum states, “If
they start becoming jaundiced, they can be saved by a transfusion from the dam.
Yes, the dam! Her antibodies that have gotten into the kitten will not
attack their own blood type (the dam's). Of course if the vet has a typed
donor, you can get by with that also. Of course with kittens so tiny, a
transfusion is tricky to say the least.”
If the B type cat is a male, the male can be bred to a B female or an A female with no kitten issues. However it is probably wise to bred the “B” type male to an A/A female. The next generation will be all A blood type but heterozygous (A/B). The following generation, if the A/B is bred to a homozygous A (A/A) cat - all will still be A blood type and only 50% will be A/B. This program will help one work towards having all “A” blood type cats in the breeding program.
The charts below demonstrate the optimal solution for eliminating the B blood type in a breeding program using a B blood type male:
Generation 1:
In generation 1, 100% of kittens are blood type A, but all are carrying B blood type.
|
Generation 1 |
MALE |
||
|
B |
B |
||
|
Female |
A |
A/B |
A/B |
|
A |
A/B |
A/B |
|
Generation 2:
All kittens are blood type A. 50% of kittens are homozygous for blood type A and 50% are A carrying B blood type.
|
Generation 2 |
MALE |
||
|
A |
B |
||
|
Female |
A |
A/A |
A/B |
|
A |
A/A |
A/B |
|
From generation 2, a breeder can DNA test and select to keep one of the homozygous A blood type kittens. Of course, we cannot ignore the possibility that these are just statistics and all may still be heterozygous. Also some cases, health and breed type may outweigh the blood type consideration as well.
Conclusion:
The amount of “B” blood type in the Sphynx is so high right now, we cannot eliminate all B blood type cats immediately from our programs without having a detrimental effect on the breed. The answer is that we need to work towards getting our population to be homozygous “A” type. This can be successfully done with the use of DNA tests that are available.
There is no good reason not to DNA test all cats in a breeding programs now. Blood typing can save feline lives. Using UC Davis DNA blood type test, http://www.vgl.ucdavis.edu/services/cat/, it is a simple non-invasive, fast and very inexpensive. The more information we have, the more power we have to maintain a successful and healthy breeding program.
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