[ SHOWGSD-L ] Re: OVC vs OFA
- From: "Liz" <RockyLizard@xxxxxxxxxxx>
- To: "The List" <showgsd-l@xxxxxxxxxxxxx>
- Date: Sun, 25 May 2008 10:32:33 -0600
I think I can reply somewhat knowledgeably to this question, with a personal
OFA vs OVC experience.
My Ch Ivan (RIP sweet boy) OFAd good hips but had one elbow come back "DJD
I". I sent those same x-rays off for not one but two second opinions. DJD
I might not, in itself, necessarily be a big deal but I personally wanted to
find out what was behind it, in case that WAS a big deal.
The 1st second opinion was OVC, who gave him a number--certified him.
Didn't even notice the little sclerotic spot that OFA had noticed, and my
vet had pointed out to me afterwards.
The 2nd second opinion was a board-certified vet radiologist diplomate, so
definitely a highly qualified very-good-at-what-he-does sort of radiologist.
That guy wrote my vet back and said "yes, I see something. In order to
determine if it's a problem, I need another view." So, we sent him some
more views, and he came back with the opinion "Ivan is within the normal
range."
So these are the benefits and drawbacks, IMO, of OFA and OVC.
OFA has 3 very highly qualified vet radiologists read your dog's x-rays.
OVC has ONE. Obviously he's human and one guy might miss some things.
There was DEFINITELY something there on Ivan's elbow x-ray, and sometimes
there might be a greater problem but at 24 months old the only symptom might
be "DJD I". So I sort of lost a little faith in them since OVC completely
missed whatever that was.
OFA and OVC both look at only ONE x-ray view, the flexed medial to lateral
view. That view can not necessarily see anything and everything going on
with a an elbow. This is why I found a board-certified veterinary radiology
diplomate that will look at more than just that one particular view to use
as a 2nd opinion in case of a DJD issue with a dog.
Now as to the matter of re-submitting a dog and the dog getting a better
rating, OFA actually addresses this themselves, on their offa.org website.
They say:
"Breeders do sometimes resubmit the same dog using a different set of
radiographs, and this can occasionally result in a different evaluation. The
evaluation can be influenced by a number of factors, such as density,
contrast, and positioning (similar to the effects that focus, lighting, and
camera angle might have on a photograph). Correct positioning and good
radiographic technique will result in the most accurate evaluation."
They go on to say, regarding our breed specifically:
"OFA statistics for German Shepherd Dogs provide an excellent example of the
actual consistency and reliability because the OFA has performed more than
19,000 GSD elbow evaluations. Of these, 1326 dogs were resubmitted for a
second evaluation, and another 40 dogs were submitted for a third
evaluation. In 87% of the resubmissions, there was no change from the
initial evaluation. In 10% of the resubmissions, the change was from normal
to dysplastic. The majority of the initial evaluations in these cases were
preliminary reports, with the change most likely due to the onset of DJD as
the dog matured. Development of these secondary arthritic changes
contributes to greater accuracy in evaluation of dogs over 24 months of age
as compared to preliminary reports. The remaining 3% (less than 50 cases)
were evaluations that went from dysplastic to normal. Possible explanations
for the change from dysplastic to normal include a) single reading on
preliminary reports versus three readings on of age evaluations, b)
differences in radiographic positioning and technique, c) differences in
radiologists' opinions, and d) discrepancy in dog identity."
Reading between the lines, then, 87% of resubmissions had no change, and 10%
were worse, so 97% of resubmits were either the same or worse. That leaves
THREE percent that had changed for the better. OFA suggests that
explanations for the 3% that improved are: 1-For prelims, only one guy reads
the x-ray (vs 3 on an actual OFA eval); 2-better x-rays; 3-radiologist
opinions differed from the first time; and 4-the 2nd x-ray being a different
dog from the 1st. (Which is why I do "VPI or "verified permanent ID" on my
OFA submissions.)
As to age at submission, our dogs are still growing, changing, and maturing
up to and sometimes even past 2 years old. I personally would trust less an
earlier x-ray than one past 24 months. I read a study (can't find it right
this second but will look for it) that said some THIRTY PERCENT of joint
evaluations change for the WORSE between 12 months and 24 months.
Just my opinion but having had dogs with DJD I issues a couple of times I
got into this pretty deeply. To me, the bottom line is DJD I is not, in
itself, necessarily a big deal as long as you can find out what is, or IS
NOT, causing it. Neither OFA or OVC are very helpful with this since they
only look at one x-ray view. I personally trust OFA more than OVC because
of my experience with Ivan, and one radiologist vs a consensus of 3
radiologists...well, 6 eyes are better than 2, no?
So...for what they are worth, those are my thoughts on the subject.
Liz in Utah
----- Original Message -----
From: "Rebecca Little" <pbgs@xxxxxxxxxxxx>
To: "The List" <showgsd-l@xxxxxxxxxxxxx>
Sent: Sunday, May 25, 2008 4:23 AM
Subject: [ SHOWGSD-L ] OVC vs OFA
>I asked the question on another list(an agility list) if I should wait to
>do OFA or should I do OVC since I can have the dogs xrays done earlier
>(18mos) so then they(daughter and dog) could compete in agility. Well this
>opened a can of worms so to speak. The majority of people had not heard of
>OVC then a talk insued about cases of OVC passing a dog when OFA had failed
>them. I personally have lost some faith on OFA by watching some of the
>things that happen...dog is given a mild rating 6 mos later dog gets a
>borderline, then 6 mos later the dog gets a fair. How is it the dog gets
>better with age.
> My question is how does the show community feel about OVC vs OFA. Does
> everyone feel they are more accurate then OFA? One person commented on the
> other list....so if your dog does not pass OFA then OVC will pass them? I
> told them its not like that, sometimes OFA is wrong but I would love to
> hear what others say. I personally have NEVER used OVC. Also why is the
> OVC not listed on the GSDCA's website since so many members use them?
> Lastly I would like to ask if I could cross post some of this discussion
> so I can enlighten the GSD agility list. I think its important since it
> appears half of the dogs on there have failed OFA.
> Rebecca Little
> Peakes Brook German Shepherds
> http://sites.centralpets.com/mammals/peakesbrookgsd/index.html
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POST is Copyrighted 2007. All material remains the property of the original
author and of GSD Communication, Inc. NO REPRODUCTIONS or FORWARDS of any kind
are permitted without prior permission of the original author AND of the
Showgsd-l Management. ALL RIGHTS RESERVED.
ALL PERSONS ARE ON NOTICE THAT THE FORWARDING, REPRODUCTION OR USE IN ANY
MANNER OF ANY MATERIAL WHICH APPEARS ON SHOWGSD-L WITHOUT THE EXPRESS
PERMISSION OF ALL PARTIES TO THE POST AND THE LIST MANAGEMENT IS EXPRESSLY
FORBIDDEN, AND IS A VIOLATION OF LAW. VIOLATORS OF THIS PROHIBITION WILL BE
PROSECUTED.
For assistance, please contact the List Management at admin@xxxxxxxxxxxx
VISIT OUR WEBSITE - www.showgsd.org
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