PENNHIP XRAYS VERSUS OFA HIP XRAYS
I was part of a Yahoo Group that discussed the pros and cons of PennHIP and OFA Hip xrays.
This is an excerpt from a post I put on the list on my personal views of PennHIP and OFA. Many people don't understand the difference in what PennHIP and OFA look for and therefore are confused. I found giving an analogy to puppy buyers helped to explain the difference. This analogy has also since been used by other breeders (with my permission and credit given to me) and on other breeders websites:
"If your dogs hips and the surrounding hip area were the wheel area on your car:
OFA would look at the wheels themselves to make sure it is the correct size for your car and had the proper tread. They would look at rotors, calipers and brake pads to make sure that they are smooth and unworn and installed properly. And if something was not correct size or worn or not fitting properly, they would grade it based on how incorrect or worn it is.
PennHIP would look at how tightly that wheel fits on the rim. Are all the bolts screwed in tight so it does not wobble.
Because if you have a car with the proper perfect wheels, brakes etc, and the lugnuts are not tight and the wheel wobbles going down the highway, eventually it will wear those perfect tires and surrounding area out quicker.
And if your car has nice tight tires on the rim, but some of the other parts are not correctly spec'd, you could also eventually wear out some parts earlier than expected."
In essence, I believe both xrays need to be performed to give an accurate look at the hip structure for breeds that are prone to dysplasia such as shepherds (and bulldogs).
And if you couldn't tell, yes, I do work in the automotive industry.
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WHY IS IT IMPORTANT THAT BOTH PARENTS HAVE NORMAL HIP AND ELBOW CERTIFICATIONS?
Hip and elbow dysplasia (among other orthopedic maladies) are genetic in nature.
The Orthopedic Foundation for Animals (OFA) is the "gold standard" for grading hip and elbow xrays. Let's just take a look at what the OFA says about elbow dysplasia.
http://offa.org/edanswers.html
Please see Example 1 from the article:
Even if both parents have OFA normal elbows, on average, 1 in 8 (12.2%) puppies will have elbow dysplasia. So one may ask, why xray and use normal elbow parents...cause you are still producing dysplastic puppies?? Well, in the same example, if one parent has OFA normal elbows and one parent has dysplastic elbows, about 1 in 4 TO 1 in 3 (26.1%-31.3%) puppies will have elbow dysplasia...YOU HAVE JUST SIGNIFICANTLY INCREASED YOUR ODDS OF DYSPLASIA IN YOUR PUPPY by having one parent with dysplastic elbows. And if both parents have dysplastic elbows, about 2 in 5 (41.5%) puppies will have elbow dysplasia. Need I say more?? This is the reason I require anyone who brings me a female shepherd for stud service to have official OFA hip AND elbow certification passing results.
What about breeding dogs with only Grade 1 (the mildest) form of elbow dyspasia?
Please scroll down in the article where it begins "Other countries..." and read:
Using affected mates not only created more affected progeny, but created more progeny with more severe grades of elbow dysplasia.
A statistics lesson to make you think a bit more -
It was mentioned above that using just one parent that has elbow dysplasia produces about 26.1-31.3% of puppies with elbow dysplasia.
http://offa.org/stats.html#breed
The average elbow dysplasia rate for a German Shepherd is 19.4%. Ask yourself, why would a breeder use a dog with elbow dysplasia knowing that the puppies produced will have a greater chance of having elbow dysplasia than what the average for the breed is. And especially since we know that using a dysplastic parent will create puppies with more severe grades of dysplasia!
WHAT ARE PRELIMS?
Prelims or Preliminary Xrays are just that...preliminary!
OFA does not give official certification to hips and elbows until a dog turns 2 years of age. However, some breeders want to know the status of their dog before that time or to breed their dog before 2 years of age. Prelims are not official certifications!
Again, the Orthopedic Foundation for Animals (OFA) is the "gold standard" for grading hip and elbow xrays. Let's just take a look at what the OFA says about prelims.
http://offa.org/hipprelim.html
To be clear here, a normal rating is a rating of Excellent, Good or Fair. So if a dog has a Good prelim, it has a 97.9% chance of having a normal rating (Excellent, Good or Fair)at 2 years of age...while a dog that has a Fair rating has a 76.9% chance of having a normal (Excellent, Good or Fair) rating at 2 years of age. For that Fair prelim...that means that there is a 23.1% chance that the dog will be dysplastic at 2 years of age. BEWARE of prelims!
Now the above makes Good prelims look good! But it also depends upon how old the dogs was when the prelim was done. Read further in the article:
Reliability at 3-6 months of age is 89.6%, that means that a very young dog prelimm'd normal has a 10.4% chance of being dysplastic when 2 years of age.
Many breeders do prelims at one year of age, reliability at 7-12 months of age is 93.8%, that means that that adolescent dog prelimm'd normal has a 6.2% chance of being dysplastic when 2 years of age.
Some countries give hip&elbow certifications at 12 months of age.
Some countries give hip&elbow certifications at 18 months of age.
OFA (in the US) does not certify hips&elbow until 24 months of age.
Please note: OFA certifications show up on the ofa website: offa.org - - click on "search OFA record" - - enter dog's registered name in the "part of name" field. Please doublecheck the parents of the puppy you are interested in to be sure that they have certified hips and elbows (Certified hips and elbows have an OFA number - preliminary have the word preliminary in the "final conclusion"). Many breeders will advertise OFA Hips/Elbows when they are just preliminary. Many breeders will advertise Xray'd Hips/Elbows that were never sent to OFA and only xray'd and commented on by their veterinarian and not an expert. You can always doublecheck the parents status at the OFA website: http://offa.org/
A statistics lesson to make you think a bit more -
It was mentioned above that a fair prelim means that the dog has a 23.1% chance of being dysplastic at 2 years of age.
http://offa.org/stats.html#breed
The average hip dysplasia rate for a German Shepherd is 19.1%. Ask yourself, why would a breeder use a prelim dog that has a greater chance of being dysplastic than the average for the breed. Especially, when we know from the elbow example that a parent who is dysplastic creates more dysplastic puppies with more severe grades of dysplasia!
Know what hip&elbow certification the parents of the puppy you are interested in have....and at what age it was given! Prelims are just that...preliminary!