Thursday, June 3, 2010

Don't Throw The Baby Out With The Bath Water

Many of the problems we encounter in dogs, both purebred and mixed breed, can be classified as hereditary, although the mode of inheritance is often complex and dependent on the actions of a number of genes. Each breed has it's own list of potential problems, and mixed breeds can inherit a variety of problems from their assorted ancestors. (No, they are NOT healthier.)

Some of these inherited traits are only tendencies that can be modified with proper care. For instance, both shyness and aggression can be inherited, but in many cases they can be modified with proper training and socialization. The same is true of structural issues like hip dysplasia - in breeds where it is common problem, pups that are allowed to carry too much weight while growing seem to be at increased risk. Excessive supplementation has been tied to other orthopedic problems in growing pups. Atopic dermatitis is a commonly inherited allergy in dogs, but some dogs will have serious allergies while others will be only mildly affected because of differences in diet & environment. Responsible breeders try to minimize the possibly inherited problems when they plan a breeding, but it's impossible to prevent everything. A famous geneticist explained to us at a seminar that we have to decide whether a problem is serious enough to eliminate all potential carriers from a breeding program, but if you also eliminate the dogs who produce minor/manageable issues, you might end up eliminating the entire breed!

A reader posed an interesting question -
i bought a puppy who at about ten weeks old began displaying signs of entropion (spelling?). we took her in and the vet "tacked" her eye lids and now she is just fine and you can not even tell that she had the procedure done. it caused no damage whatsoever. i was talking to a friend today whose mastiff puppy had the same condition, only much worse. she told me that my puppies' parents should never be bred again because entropion is hereditary. is this true? my puppy's sire is a champion and has produced several litters (and a couple champions). is this problem always hereditary? thanks.

Entropion is characterized by one or both eyelids rolling in, causing eye irritation and damage as the hair rubs on the eyeball. It's more common in breeds with excessive skin folds (like Chows & Shar Peis) but can show up anywhere. It's considered a serious problem in Mastiffs, but not in Dalmatians, and its not at all common in this breed. I've only seen one affected pup in 40 years, and it was in a puppy bitch I purchased about 10 years ago. One of her eyelids started rolling when she was about 4 months old. My Vet "tacked it" (a few small stitches to help it stay in the correct position) and explained to me that this was normally enough to allow the eyelid to tighten as the dog "grew into" it's facial skin. Had it been successful, I would probably have shown her but not bred her. The tacking didn't work and she eventually had surgery, was spayed, and was placed in a pet home.

This pup came from a pedigree that I was very familiar with, dogs from breeders who I knew well. None of them had ever seen a case of Entropion. Several of her littermates have produced multiple litters without producing a single case of Entropion and some really fine dogs have come from this pedigree.

Because this is not a problem in the breed, because it can be related to a variety of developmental factors, and because it is normally easily managed, I do not agree that the parents should never be bred. The breeder needs to be informed that this happened, and should check on the littermates and any other dogs produced by the parents, but one isolated case is not sufficient reason to stop breeding the parents.

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