Dog Discoveries

How Do Dogs End up Being Bow Legged?

 

We are used to seeing bow-legged dogs in cartoons or in company logos meant to give a rugged, imposing image to their business, but in real life, bowed legs can be a serious problem in puppies and adult dogs. Bowed legs in dogs are an abnormality that is noticed when a leg grows curved or bowed instead of appearing straight as it normally should. This type of abnormality is most likely to be seen in young, growing due to problems in their development, but can also be seen as an aftermath to traumatic injuries sometimes even in older dogs. Whatever the cause, it’s important to consult with a vet to determine the best course of action.

puppy growth plateThe Aftermath of an Injury

When puppies are developing, the long bones of their front and back legs are gradually growing, courtesy of growth plates, also known as ephiphyseal plates. These growth plates consist of  soft, cartilage matter located at the end of the puppy’s bones. Growth plates tend to close when the puppy is 12 to 18 months of age. Around this time, the soft cartilage at the end of the bones hardens and mineralizes into hard bone.

If an injury occurs before the growth plates close, there are chances that the cells on the damaged side of the growth plate quit growing, while the cells on the non-damaged side continue to grow, leading to uneven growth and its associated curving, which ultimately leads to bowed legs. Traumatic injuries that may cause bowed legs in a puppy include being hit by a car or the puppy being accidentally dropped.

“An impact such as taking a fall and landing on the front limb with full force can drive this cone-shaped growth plate together and result in severe damage to the cells. This type of injury is common in short-legged dog.” ~ Veterinary surgeon, Dr.Daniel A. Degner,

Breeds with Bowed Legsachondroplasia

In certain breeds, the appearance of bowed legs may be genetic, which means it’s passed down from one generation to another. The American Kennel Club’s Bulldog’s breed standard calls for short, very stout forelegs that are straight and muscular, set wide apart and have a “bowed outline;” however,  the bones of the legs should not be curved or bandy. This particular conformation is what gives the bulldog its peculiar, shuffling, “rolling” gait. In other dog breeds, the bowed legs are due to a mutation in the gene responsible for converting cartilage to bone leading to what is known as “acondroplasia.” In these breeds, the bones of the legs appear shortened and deformed with bowed forelimbs. Common achondroplastic breeds include the basset hound, dachshund and corgi. In these breeds such bowing is acceptable, up to the point of being desirable in their breed standard.

In other breeds, bowing of the legs is considered a serious fault.  Just like bad hips and eye and heart conditions can be passed down from one generation to another, bowed legs may be hereditary and considered an unappealing trait that breeders try to avoid from happening through careful breeding protocols. However, in some cases, temporary bowing may appear in certain breeds of dogs when they’re puppies. Veterinarian Dr. Deb, mentions that Rottweilers are a breed that tend to look “hocky” as they develop meaning they appear to be bow-legged in the hind legs but the good news is that most pups outgrow this as they mature.

puppy weaningNutritional Problems

At times, bowing of the legs may be attributed to a nutritional imbalance. This is not common as it used to be, as most dog foods are now produced to be nutritionally complete, but occasionally, breeders may be feeding a homemade diet that isn’t nutritionally complete as it should and this may have an impact. Raw and homemade diets for puppies can be risky if there’s a disruption in the calcium/phosphorus balance. “Homemade raw diets  have been associated with nutritional imbalances, leading to skeletal problems in growing puppies,” warns board-certified veterinary nutritionist Dottie Laflamme. Rickets is a a nutritional imbalance of phosphorus or vitamin D in the diet which has been known to cause outward bending of the shafts of the long bones in dogs, poultry and certain farm animals.

“Rickets: Signs may include bone pain and swelling, a stiff gait or limp, difficulty in rising, bowed limbs, and fractures.” Merck Veterinary Manual

Seeing the Vetdog pain goes away at the vet

The above are just a few of the common reasons why puppies may have bowed legs. While bowed legs may seem like a cosmetic issue, in reality these limb deformities risk causing the dog to move in an abnormal manner which can lead to pain and arthritis. Anytime a puppy goes through a traumatic injury, it’s important to see the vet. The bowing does not occur right away, but generally about 2 to 4 weeks later. It’s important to carefully monitor the leg and compare it to the non- injured one so to recognize early signs of trouble. An orthopedic exam done by a vet, or even better, an orthopedic surgeon can determine what may be causing the bowing along with the best treatment.

 

Did you know? There’s a good reason why veterinarians and dog trainers discourage vigorous jumping and other forms of strenuous exercise in puppies: those growth plates are very vulnerable! It’s a good idea to wait until these growth plates close and seal before engaging the pup in vigorous activities and canine sports.

 

References:

  • Black’s Veterinary Dictionary, By Edward Boden, Rowman & Littlefield Publishers,; 19th edition (1998)
  • Merck Veterinary Manual, Disorders Associated with Calcium, Phosphorus, and Vitamin D in Dogs, retrieved from the Web on April 17th, 2016
  • Vet Surgery Central,  Angular Limb Deformity, retrieved from the Web on April 17th, 2016

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