Today I copied a message from Pennhip, answering several of my questions.
explaning the different between OFA - FCI x-ray results.
Worth to study this directly behind the first part of PENNHIP!!
Canine Hip Dysplasia (CHD) afflicts millions of dogs each year and can result in debilitating osteoarthritis (OA) of the hip. It is estimated that more than 50% of the most popular large breed dogs will show x-ray evidence of CHD. Many will suffer from osteoarthritis, pain, and lameness, costing owners and breeders millions of dollars in veterinary care, shortened work longevity, and reduced performance.
PennHIP (University of Pennsylvania Hip Improvement Program) is a not-for-profit program, wholly owned and operated, by the University of Pennsylvania. It consists of 3 integral components:
The way hips are evaluated by PennHIP is very different from the way the OFA or the European FCI does, or the other hip screening system for that matter. Both OFA and FCI look at one radiograph which is the hip-extended view, a radiographic view taken from human medicine, where the dogs lies on it's back and legs pulled straight. The way the animal's legs are positioned in this view often masks hip laxity so that the hip joints appear to be tighter than they really are. (laxity has been regnized as the first sign of hip dysplasia since the 1960s and it is the laxity that leads to the painful osteoarthritis of hip dysplasia) PennHIP looks at three different views of the hips, it asses the hip-extended view that OFA uses only for signs of arthritis, the other two views are the compression and distraction view from which the passive laxity can be measured. It is not a subjective system like OFA or FCI, but it is a measurement that is taken directly from the radiograph and is highly repeatable.
The measurement is the distraction index (DI) which is a number between 0 and 1, the closer to 0 the "tighter" the dogs hips, the closer to 1 the "looser". The looser the dogs hips are the more likely he/she is to develop osteoarthritis. Studies have shown that dogs with a DI of 0.30 or less (0.28, 0.25 etc) do not develop arthritis and are thus considered to be truly "normal" hipped dogs. The study also showed that the probability of developing arthritis increases as the DI gets closer to 0.7, meaning a dog with a DI of 0.7 has almost a 100% chance of developing the osteoarthritis of hip dysplasia.
Unfortunately many dog breeds have an inherent laxity in the gene pool so that the majority of dogs have DIs far above 0.30. If only dogs with DIs of 0.30 or better were permitted to be bred, many great animals would be excluded from breeding and the degree of inbreeding would increase. Therefore, PennHIP has developed a way of comparing one individual with all the other members of the same breed (as long as there are at least 20 in the group). The breed average is considered the 50th percentile so for Golden Retrievers (for example) the DI would be 0.54 as of May 2009. PennHIP recommends breeding Goldens with DIs better than 0.54 so dogs in the 60th (0.50) or 75th (0.44) percentile to achieve improvement in the breeds hip profile. It is expected that DIs will move toward tighter hips (so 0.30) from one generation to the next as genetic improvements are made, so that a dog in the 60th percentile in 2012 will have a tighter DI than a dog in the 60th percentile in 2008.
Now, comparing OFA and PennHIP scores. OFA uses only one radiographic view to evaluate the hip joint, which often masks hip laxity merely by the way the animal is positioned. OFA is very good at identifying hip dysplasia (CHD) positive animals, so there are very few "false positive" results. However OFA does not find ALL the dysplasia positive dogs, so there are many "false negatives" (meaning dogs that have CHD are considered to be dysplasia free by OFA). A high percentage of dogs passed as OFA excellent, good, or fair and certified for breeding carry the genes for CHD. Our data show that 56% of dogs receiving OFA Excellent hip scores are, in fact, susceptible to the OA of CHD: 82% of the OFA Good scores are susceptible to OA of CHD; and 95% of OFA Fair scores are susceptible to the OA of CHD. These data explain why we are making such slow or no progress in eliminating or even reducing CHD using the OFA method. We are currently conducting simliar comparsons with the British BVA, Australian AVA and European FCI systems.
The conclusion: A high proportion of dogs certified for breeding by the OFA, carry the genes for CHD.
It appears to me that many breeders take advantage of the PennHIP system since it does not give a "pass" or "fail" score. Hip dysplasia is a multi-factorial disease that is not as simple as yes or no/ pass or fail. The purpose of performing hip screening is to find those dogs with the most normal hips and to breed selectively with these individuals. It is also a common misconception that just because PennHIP does not give pass/fail grades that it is easier to "pass". As a matter of fact PennHIP is a stricter grading system than OFA or FCI meaning that many dogs that "pass" these other tests are not in the top 50th percentile for PennHIP and thus not considered to be breeding candidates. It may be that breeders are not taking percentiles into consideration when breeding their animals, but the truth of the matter is, PennHIP gives a true and exact evaluation of the laxity in a dogs hip joint and it will provide you with information regarding your dogs probability of developing painful arthritis.
Unfortunately we do only have 8 Slavinsky Cuvac in the pennHIP database at the moment. Their DIs range from 0.33 to 0.84, we cannot calcualte percentiles according to this breed, so right now we are compring them to ALL the dogs in the database. Once there are 20 Cuvac we can start ranking them among themselves.
I hope this has helped answer some of your questions, again I appologize for the delayed reply.
Please feel free to contact me with any further questions.
Sincerely,
Georgia Karbe, med.vet.
PennHIP Post Doctoral Research Fellow
PennHIP Administrative Center
3900 Delancey St.
Today was a big day.
First time x-ray of Girly... Dara spod Babej hory.
First time with the Penn-hip-system.
Everything new for me, but I studied the website www.penn-hip.com, before I visited the Veterinarian Hospital in Sugarland.
You need a Vet, who has the license with Penn-Hip (PA Univerity)
So I met Dr. Quick and he explained everything, what he planned to do and the different way of OFA and Penn-Hip.
OFA only check the x-ray pictures (dogs must be 24 months old) and give the result. Even there are bad pictures offered for the result.
But the OFA rule is 24 months, this is meaning, you cann't start breeding, before you have these results. So it is easyly done, that a female is coming in the 4th heat, before she can be mated.
PENN-HIP has a complete system and a specialized vet only can do the x-ray.
After getting the results, the Club rules will change to:
start to breeding with 18 months, if the hips are ok, if the teeth/bit is full developed. (more at the club rules... they will be a point on the member meeting at April 10.2009.
Dr. Quick examined Girly and found her in best health. Her weight: 65.2llbs.!!
Than he took a lot of pictures in each position.
But before, Girly got sedation.
Dr. Quick
I got a report about the x-ray:
also I got a membership form for Girly and for the Club.
it takes normaly 2 weeks, till the final result will be sent by Penn-Hip.
I will follow up with more explanation and infos about Penn-hip.