HIP DYSPLASIA IN BEAGLES

By Ruth Darlene Stewart

This article was published in the June 2001 edition of the Show Beagle Quarterly. Reproduction of written material and graphics prohibited without permission and credit.

Beagle breeders have often that thought Hip Dysplasia (HD) was not a problem in beagles because of their small stature.   That is a misconception.  While it is agreed that HD in beagles may not be crippling, if the problem is not addressed and attention given to improving and maintaining current hip structure, HD may become a crippling problem in the breed. When do breeders step forward and address the problem? Now? Or when beagles are lame from hip dysplasia?

Non-show breeders may say it is only in the show stock however, information obtained from the Beagle Brigade which utilizes beagles from the general population identifies the number one health reason for rejection of potential candidates is HD/spinal abnormalities.

Many research articles and theories about HD have been published. The best information to date is that it is a polygenic trait; meaning more than one gene pair is involved in the development of HD.  Environmental factors may also play a role in HD, but there has to be a genetic tendency for the problem.    Studies have shown that HD is not present at birth but gradually develops as the dog matures.  "Dysplasia" literally means "bad development."  A dog genetically programmed for HD was a weakened structural foundation.  Many dogs effected with HD may never show outward signs of lameness, and many times movement cannot be a diagnostic factor either. Older dogs that show stiffness are said to have arthritis, but HD is a common cause of arthritis.

There have been less than 300 beagles certified by the Orthopedic Foundation for Animals (OFA) since 1974.  This is a very low number.  OFA records show that of the radiographs being submitted 15% are deemed dysplastic.  Many x-rays may never be submitted because HD is so apparent.  If a larger number of beagles were being submitted for evaluation then the figures might be more accurately indicative of the overall population.

 Many breeders state that they have their dogs checked but do not submit to OFA.  Here are a few reasons to submit to OFA:

1. With the ever-narrowing gene pool it would be a benefit to all breeders to be able to utilize the OFA records to track certified animals.  This would help in evaluating prospective breeding partners.  Only a handful of breeders can track hip status of their line more than two generations.  If you have your radiographs evaluated by your veterinarian but not submitted;how will anyone years from now know your dog was normal?

2. OFA evaluation sets a standard that all must meet.  Too often I get breeders telling me that their veterinarian said that the x-rays were "great" and OFA has a different opinion. General practitioners are not Board Certified Radiologists.   There are Veterinariay Radiologists that do an OFA type exam, but again, that exam is not on record except in your personal files.  It does nothing to help establish a genetic database that is accessible to everyone.

3.  It is not that expensive.  The cost of OFA hip evaluation is $30.00.  Having the radiographs made is the most expensive part.  Miss one weekend of shows and have the x-ray taken, for the betterment of the breed. OFA also offers discounts for litters and kennels. One way of decreasing the expense is to have the x-ray taken when the dog is anesthetized for other reasons. i.e. dental prophy

4.  Know from where you are starting.  Always consider that if you get a fair or worse evaluation,  you need to look for a breeding partner with a good or excellent rating.

If you get an evaluation back with HD noted,  most experts will advise you to remove that dog from the breeding population.  But, since there is not an extensive genetic database on beagles regarding HD and the genetic pool is so limited, some researchers will say to breed the animal to a partner with better hips.  I would caution you on this endeavor, evaluate your beagle closely.  Ask the following questions:

Is it a fine specimen of the breed?

How is the temperment?

How bad is the HD?
Borderlines or mild may be considered carefully for breeding. Avoid breeding animals with moderate or severe evaluations.

What about other health factors?  Thyroid, epilepsy, eye problems, etc.
Only by selective breeding and consideration of ALL health factors can breeders hope to improve the breed.

When first delving into the world of HD my veterinarian taught me that "it is not all ball and socket."  Below is a brief overview of the process of evaluating hips for HD.  I am using the OFA method as a standard due primarily to the fact that is has been used for decades, it is readily available to all, and provides a tracking database.

The certification number given to a beagle represent the number of beagles certified, the age in months that the beagle was cleared, and the grade give (Excellent, Good, Fair).  A preliminary evaluation can be obtained prior to the age of 24 months but permanent certification will only be given at two years of age or older.

Figure 1 shows the proper positioning.
    a. Inclusion of the pelvis, femurs and stifles
    b. Symmetrical position
        1. Equal width of the wings of the ilia.
         2. Equal size of the obturator foramina
         3. Parallel femurs with the patella
             positioned on the midline of the
             distal femurs.
 
 
 
 
OFA will evaluate the following factors:
a. Joint space
b. Amount of femoral head within the
acetabulum. (a minimum 1/2)
c. Shape (roundness and smoothness) of femoral head.
The fovea capitus is a normal flattened area on the
femoral head.  This is where the femoral ligament attaches.
d. The femoral neck, which should be smooth and free of dysplastic changes.
e. The angle of the femoral neck which should be approximately
130 degrees.
 
 

Figure 2  A normal canine hip with the desired 130-degree angle.
 

Here are a few examples of hip evaluation IN BEAGLES from OFA.
As you look at these pictures, try to imagine the angle, the smoothness and length of femur neck and the roundness of the femoral head.  Draw two imaginary lines, one from the top rim of the acetabulaum to the outer edge and another line depicting the angle.
 
 
 
 

OFA EXCELLENT 

OFA GOOD 
 

OFA FAIR 
 

Radiographic indications of HD:

  1. An increased width of the joint space
  2. A flattening and deformity of the femoral head
  3. A shallow acetabulum
  4. Remodeling/degenerative changes of the rim of the acetabulum
  5. Remodeling degenerative changes of the femoral neck
  6. Subluxation.
OFA MILD HD 
 

Note

  1. the subluxation and the shallow acetabulum
  2. the rim changes on the upper point of the acetabulum rim
  3. the decreased angle of the femoral neck

  4.  
OFA MODERATE HD 
 

Note:

  1. the remodeling of the acetabulum rim
  2. the flatten somewhat mushroom femoral head
  3. the thicken femoral neck.

Consider checking for Hip Dysplasia.  Help establish a basis from which we can go forward  with breed improvement and avoid future problems.  For more information about OFA and to check the existing database please visit their site  www.offa.org


 

Reviewed By G.G. Keller, D.V.M.,M.S.,DACVR, Executive Director, Orthopedic Foundation for Animals, Inc.


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