Labrador Retriever running in field
Does your dog wag his tail so hard in greeting or excitement that he bashes it against doors, walls, fences or the sides of a kennel until it’s bloody? He’s not alone. It’s not unusual for large dogs with smooth, thin tails — think Labrador Retrievers, Great Danes, Greyhounds and Pit Bulls — to injure their wildly wagging appendages in this way.

In my practice, I’ve seen many dogs, mostly Retrievers, with this condition. They wag their tails so vigorously that they lift alternate back legs off the ground! We veterinarians have a nickname for this condition: happy tail syndrome.

When owners come in with a dog whose tail has a bloody tip, I say, “Your dog smiles too much.” They look at me quizzically, and I explain that dogs “smile” with their tails, adding, “Your dog smiles more than a Walmart greeter or an NFL cheerleader.”

How It Happens

A dog’s tail has anywhere from five to 20 vertebrae, known as “caudal” vertebrae, because they are positioned toward the rear of the body. Some dogs have long tails covered with short hair or thin skin. In addition, the tail has a good supply of blood vessels.

All of these anatomical de-tails, if you will, contribute to the possibility of happy tail. When you add in the dog’s large size, the force at which these pooches can wag their tails can cause serious damage to the tip of that thin-skinned tail when it hits a hard surface multiple times or over a long period.

The skin at or near the tip of the tail gets abraded so much so that it starts to bleed. Smaller dogs or those with short or extra-furry tails are less likely to suffer this type of injury.

When you have a dog like this, you may come home to what looks like a murder scene with blood spattered all over the area where the dog has been wagging his tail. If this occurs multiple times, the dog can develop a bleeding ulcer on the tip of the tail.

Hard Times for Tails

Tails with cuts or lacerations caused by being thwacked against a hard surface may need to be bandaged or sutured, depending on how serious the injury is. The wound can sometimes become infected and require treatment with antibiotics.

Bandaging the tail helps it to heal by preventing further injury. To keep the dog from chewing at the bandages, it may be necessary to coat them with bitter apple or some other bad-tasting substance, or to fit the dog with an Elizabethan collar to prevent access to the injured area.

Some dogs just never figure out not to wag so vigorously. If a dog keeps injuring the tail and is in constant pain or causes frequent bloody messes, you may need to consider tail amputation.

Dogs have tails for a couple of reasons: The tail serves as a counterweight or rudder for more effective or precise turning when the dog is running, and it signals social cues. Those are important purposes but not essential. If taking the tail off will solve the problem of happy tail syndrome, rest assured that a tail isn’t an essential piece of anatomy for your dog.

In fact, consider a bobbed tail the world’s greatest doggy grin.

More on Vetstreet: