lunes, 28 de noviembre de 2011

Genetic (and other) Testing Helps with Breeding Decisions

Determining whether or not a dog should be used for breeding is not always easy, which is just one of the reasons why I cringe when I hear pet owners say that they want to breed their dog "for the experience," or "to have one of his or her offspring."

Responsible breeders put a lot of money and effort towards making sure that only the healthiest individuals pass their genes on to the next generation.

One way breeders can do this is via genetic testing. Many of the diseases that most frequently affect purebred dogs have a genetic component, meaning that at least in part, a dog’s DNA determines whether or not he or she develops the disease in question. When the inheritance pattern for the disease is relatively straightforward (i.e., a single gene is responsible and it is passed on in a simple dominant/recessive pattern), DNA testing can mean the difference between a litter of healthy pups and a nightmare of medical consequences.

DNA testing is powerful. It can be performed at any age, which reduces the chance that a problem will be detected after litters have already been produced. It also provides fairly definitive results, resulting in fewer judgment calls that can allow "bad" genes to remain in the population. No test is infallible however, so always analyze the results in combination with all the information that you have available.

Unfortunately, the inheritance of some canine diseases is very complicated, which means that DNA testing is not feasible, at least for the time being. When multiple genes are involved or environmental factors play a large role in disease expression, looking at the dog’s body (e.g., phenotypic testing via exams, blood work, X-rays, etc.) is the best option we have available. This is a less than perfect situation, because individuals may not have symptoms themselves but can still pass on abnormal genes to their offspring, or they may not have a detectable disease until later in life, after they have already been bred.

To learn about all of the different types of tests that are available, check out these resources:

  • The Orthopedic Foundation for Animals a listing of "currently available DNA tests"
  • The Canine Health Information Center lists breeds that are enrolled in the CHIC program and include associated lists of recommended genetic and phenotypic tests for each breed

If you are considering purchasing a purebred dog, go to these sites, search for the type of dog you are interested in, and then ask breeders for their results. If they look at you with blank expressions or try to evade your questions, move on to a different breeder. Owners can also use these websites to learn about some of the diseases that their pets might be predisposed to. Talk to your veterinarians to determine whether or not testing might provide you with useful information.Dr. Jennifer Coates

Meet the Mutts of the Cat World

National Mutt Day is scheduled to be celebrated on December 2. In the dog world, mutts are also known as mongrels; non-purebred dogs whose genetic heritage is made up of two or more breeds.

Rather than mutts, mixed breed cats are known as domestics. By definition, a domestic shorthair cat is a "cat with short fur that is not a pedigreed member of a recognized breed." Similarly, a domestic longhair cat is a "cat with medium or long fur that is not a pedigreed member of a recognized breed." In other words, our domestic cats are the mutts of the cat world.
Right off, let me say that I have absolutely nothing against purebreds or purebred breeders. Like many of you, there are many breeds of both dogs and cats that I particularly like and I would hate to see those breeds become extinct simply because nobody is breeding them any longer. If you are a responsible breeder and are breeding puppies or kittens through a planned breeding program with the intent of improving your breed, you have my full support.
I encourage anyone interested in purchasing a purebred puppy or kitten to find out what being a responsible breeder means before you buy that puppy or kitten, though. There is much more to a responsible breeding program than simply picking a boy and a girl and letting nature take its course. And please, please, please do not simply go to a pet store and purchase a purebred puppy or kitten. It is all too possible that you will be purchasing a pet that came from a puppy or kitten mill!
That being said, I love mixed breed cats. Each and every one of my six cats is a domestic shorthair. They’re all rescues and they’re all awesome. And most importantly, they’re all great pets. They are my favorite companions and my very best friends.
A couple of weeks ago, I had the privilege of attending the Cat Writers Association (CWA) annual conference and spending an entire weekend with some of the most dedicated and knowledgeable cat people I know. It was an amazing experience that I’m already looking forward to repeating next year.
Running concurrently with the CWA conference was the Westchester Cat Show, which I also had the privilege of attending. Seeing so many beautiful and often exotic-looking purebred cats was a great experience and there were some truly gorgeous cats on display. But still, I kept finding myself drawn back to the domestic cats offered for adoption by a local rescue at the show. Judging by the number of spectators that were always around the adoption area, many of the other attendees found them delightful as well.
For anyone thinking about bringing home a new cat, I recommend that you consider a domestic cat। They may not be the "bluebloods" of the cat world but, believe me, they have just as much personality and character. A "feline mutt" will make a great family member — one you’ll never regret adding to your home. I guarantee it. Dr. Lorie Huston