size-specific dog hereditary conditions

Dr. Kim Smyth
Posted by Dr. Kim Smyth on May 16 2012


Chihuahua dog sitting on larger dog | size specific dog hereditary conditions | Petplan

The Guinness Book of World Records has quite a few interesting (to say the least) statistics, but of course, my favorite entries involve our furry friends. I recently came across an article that gave me this blog’s idea, and it had to do with a rather large dog who goes by the name “Giant George.”

You see, George is the current record holder in the Guinness Book of World Records for being both the “Tallest Living Dog” and the “Tallest Dog Ever.” George is a Great Dane from Tucson, Arizona, and an unusual one, at that. He weighs in at 245 lbs and stands a towering 43 inches tall. That’s right--he’s over three and a half feet tall – at his shoulders! That’s twice as tall as your average Golden Retriever. George is so big that he sits on the couch just like you or I would!

Reading about George got me thinking about the other extreme – the smallest dog. This distinction currently belongs to a tiny little heartbreaker named “Boo Boo.” Boo Boo is a female Chihuahua from Kentucky, and stands a mere four inches tall and tips the scales at a whopping 24 ounces!

I would have loved to have been there when the two dogs met for the first time back in 2010 to promote the newest edition of the Guinness Book of World Records. It truly amazes me that two animals that are so different are actually more or less the same. A dog is a dog, right?

Well, sort of. Though they are both canines, clearly they have a few differences. And while large breed and small breed dogs alike are prone to inherit genetic diseases, the specific conditions tend to vary with size.

Let’s start with large breed dogs. This category includes big dogs like German Shepherds, Labrador Retrievers, Rottweilers, Golden Retrievers, Newfoundlands, etc. This list should also include large mixed-breed dogs. Partly due to their size, and partly due to genetics, large breed dogs are prone to orthopedic problems like elbow and hip dysplasia and rupture of the cranial cruciate ligament in the knee. In addition, large breed dogs who are deep chested are more likely to experience bloat, or gastric dilatation-volvulus.


Small breed dogs aren’t off the hook – they are also prone to their own unique set of inherited conditions. Small breed dogs include the Chihuahua, Maltese, Yorkie, Cavalier King Charles Spaniel, Dachshunds, Pug and many of the smaller terrier breeds. As is the case with the larger dogs, small mixed-breed dogs also count here, too. These little dogs have their own orthopedic problems, including patellar luxation, Legg-Calve-Perthes disease, and intervertebral disc disease. They are also more likely to have liver shunts and problems with tracheal collapse.

This isn’t to say that all large dogs or all small dogs will be affected by these conditions – because of their breeding, they are just a little more likely to occur. Because they are inherited conditions, choosing your breeder wisely will go a long way toward avoiding costly (and sometimes painful) medical conditions. Of course, if you’re adopting a pet from the shelter, you don’t have the benefit of knowing that your dog’s bloodlines are free from disease. By taking into account your pet’s size, you can be hyperaware of potential causes for concern and address them quickly with your veterinarian should problems arise. You should also consider protecting your pet with dog insurance that covers hereditary and chronic conditions, like Petplan.