Health

HD - hip dysplasia

If you own a dog you have probably heard of Hip Dysplasia, HD. This inherited malformation of the hip joint also affects cats. Maine Coon breeders all ower the world are now awear of this condition among the Maine Coons and have taken steps to reduce the presence.

In the picture far right the hip has been evaluated 3 in the Swedish scale. This is the most severe case of HD, where the cat might suffer pain and having problems with jumping and even moving. Cats with less severe cases of HD usually don't experience any problem. The hip x-rays are being evaluated towards a scale ranging from OK hips to grade 3 HD. So grade 1 HD is the mildest grade of HD, grade 2 is moderate, and grade 3 is severe. We have been recommended to for the moment also breed from cats with the mildest degree of HD. These cast are of course bred to cats free of HD.

The Swedish Maine Coon Club, Maine Coon-katten, is registering the test results in an open registry, open in January 2000. Responsible breeders x-ray their cats at the age of 1 or later. The pictures are then sent to Lars Audell, a specialist, who is judging them according to the Swedish scale.

HD is probably inherited polygenetic, meaning that many genes are involved. This means that you might get a kitten with severe HD out of two parents with good hips, and you might get a kitten with good hips out of two parents with severe HD. But it is not very likely. Among dogs a selective breeding has reduced the presence of HD radically.

Read more at Feline Hip Dysplasia Awareness Web Site, and at S*Ylletrollets Hip Reference Page you can see lots of examples on x-rays!

HCM - hypertrophic cardiomyopathy

Hypertophic Cardiomyopathy, HCM, is a heart disease where the wall of the heart grows thicker until the blood is no longer able to pump through. The are no cure and the cat will sooner or later die. With an ultrasound the disease can be detected.

As HCM is a progressive condition it takes a few years until the disease appears. In males it is usually possible to detect at 2 years of age, while in females it takes in average longer to develope.

HCM is, according to some studies, inherited by a single dominant gene with incomplete penetrance. If this is true futher research will show.

By testing for HCM we reduce the risks of breeding from cats who carry this gene. The tests are not 100% sure though, mainly because of the incomplete penetrance. But at the moment ultrasound testing is the best tool we have to control it and to reduce the risks.

Read more at Feline Hypertrophic Cardiomyopathy.

In 1998, one of the kittens I had bred, died in HCM, not even 2½ years old. It was a big chock at first, and I started to test my breeding animals, to avoid that it would happen again. In 2004 Maine Coon-katten, the Swedish maine coon club, started up a health program, and from then I follow their testing recommendations. I also only use tested males to my females.

THE GENEPOOL - the more the merrier

By Ulrika Olsson, S*Ylletrollets Cattery

Except for testing our breeding cats for genetic diseases, we think that it is very important for the future of the breed to work to maintain and broaden the genepool, to avoid future problems from inbreeding. There are many foundation cats and foundation lines behind the Maine Coons, but through the competition for the best looking cats over the generations some lines have been overused, while some have almost vanished completely. As a result today about 70% of the genepool internationally comes from only five foundation cats! Of course that is too much to come from that few cats. So what we do is to try to reduce the amount of primarily the two most common foundation cats, but also the others, in our pedigrees. This is done both by saving what is still left of other old foundation lines and by introducing newer foundation lines from Maine.

Top 5
The five most common foundation cats were living in the 1960s' and 1970s', and they are:

We usually call these cats the top 5. And we are calculating the amount of them, as one tool of knowing how interesting a pedigree is from an outcross point of view.

The amount of the two most common cats, Andy Katt of Heidi Ho and Bridget Katt of Heidi Ho, we call the percentage of Heidi Ho (or top 2).

The clones
Then we also calculate the amount of clones in the pedigrees. The offsprings of Heidi Ho Sonkey Bill and Tanstaafl Polly Adeline of Heidi Ho were born 1979-1982. They all looked very much the same, and a judge once asked what they did to make them all look so similar. "Do you clone them?", she asked. And since then these brothers and sisters are called "the clones" among the Maine Coon breeders. The clones were very successful at shows, and soon most breeders wanted one or two clones for breeding. Then many inbred on these cats, to get even better looking cats. Today about 40% of the genes in the genepool come from only these brothers and sisters that we call the clones.

Read more at The Maine Coon Heritage Site.

Thank's to Ulrika and Karolina for letting me use your texts! :)

 

And you can always contact me if you have any questions!