We were having a discussion about crossbreeds being healthier or hardier than purebreeds, why are genetic ilnesses bred out, what ime trying to say is why dont the genetic/breed related ilnesses of each breed in a dog with multiple breeds why doesnt the dog be more at risk from having the ilnesses common to each breed. ime finding it hard to explain, ime just curious as to why.

They are more likely to inherit more problems. But I suppose only have half the chance. A straight cross between 2 breeds would have a good chance of inheriting problems from either parent but as they dilute the problems will become less likely to be passed on. So if you have a Lab cross GSD you probably have as much chance of hip dysplasia as if they were pure of either breed but then if you cross that cross with a breed or crossbreed that isnt likely to suffer from hip dysplasia then there is less percentage chance that the pups will suffer from it. Always supposing that the original parents carry the gene for it of course.

I would say it could go either way. The dog could either get all the illnesses or none at all, it's the luck of the draw.

I have noticed that all the crosses I've had lived for longer than the purebreds I've had though

__________________

Yes ive always been told they usually live longer and ive also heard that they have less chance of inheriited ilnesses ime now wondering if its true after reading the last 2 replies, ime even more confused.

So am i, best stick to springer's

__________________

Genetics is confusing! I am no expert but basically some genes are recessive and some are dominant. If dominant then receiving the gene from one parent would give the pup the liklihood of inheriting whatever the gene is for. If recessive then it has to receive the gene from both parents. I know some coat colour genetics but not inherited illnesses etc but obviously if (for eg) hip displaysia gene is dominant then one parent can pass it on. If it is recessive (which I dont think it is ) then it would need both parents to pass it on. I might be talking rubbish here but on the assumption that some inherited problems are caused by a recessive gene then if you cross 2 breeds, one of which never carries the gene then the pups could never get the problem - but some of them would still carry the gene so if they were then mated with another dog that carried the gene they could then pass it on to their pups. Very simplified and I am sure someone else will actually know which problems are caused by dominant or recessive genes but it does give you an idea how an inherited problem could become impossible for a mongrel to inherit at some point.
As for living longer, well I suppose if they have less chance of inheriting common breed specific problems then the healthy ones are likely to live longer. But then again not every purebred dog suffers with breed specific problems. Your good old mongrels were traditionally lab/collie/terrier type crosses, all of which are long lived breeds anyway, so that could have something to do with it.

Yes that sort of makes sense, it is confusing though.
Dont know why i think of these things and the need to know, ile have to just start excepting that thing are as they are

What i an wondering now is we have purebred springers and our eldest was the younger brother of the 1st one we had and lost last year due to a genetic disease but harvey our eldest one has not got it so maybe the gene was not ressesive is that the right way round?. oh god but thanks for this reply, its enlightened me a lot.

It is a bit of a myth that cross breeds are hardier, although it does seem that heinz 57's go on forever, it's referred to as 'hybrid vigour'. As already said, it can go either way, you might get a dog that inherits problems from all the breeds in it's genetic make-up, there's no guarantees. I'm easily confused by all the recessive genetic malarky, but where you've got an illness common in both dogs, which a lot of hereditary illnesses are common, there's the chance it will be passed on. My last rescue, Chloe, was a Lab/collie cross, she had bad joints, cataracts, and a deformed soft palette, as well as the occasional bit of a dodgy disposition, certainly not the healthiest of animals.

__________________
The British Association for Shooting & Conservation
Countryside Alliance



Follow my art here http://tarimoorart.blogspot.com/

You would think that a first cross dog would have 2 chances of herediting a disease and the 57's would have lots of chances of getting the genetis ilnesses of each breed in it. Or is that too simple

It's not a myth. Mixed breeds and crossbreeds live longer because their genes embody a greater degree of diveristy.

It's not a good idea to have babies with our relatives. It's so well accepted in humans that the principle is enshrined in law but with our dogs.....



(source: Breed Data Summary )