I have always used the OFA for three reasons; 1) they give you rating easy for the average pet owner to understand which is a good selling point when your customers want to know hip results, 2) more people seem to use OFA than PennHip, and 3) it's easier to find a vet who knows how to do them.
That said, I have always been interested in trying PennHip. I've been to their website, but still don't get how to read results. Am I correct in understanding that they give you numbers & %'s, but not a rating? How do you know if you're dog should be used or not? I guess I'm still confused...
I have a Golden male that was OFA tested at 8 months, decent xray and positioning, and the results came back boarderline. Had him retested today at 12 months and the xrays look great regarding positioning but the vet isn't sure if they'll pass. We're sending them in and we'll wait and see. I'm wondering if I should go ahead and have him retested again in 6 to 12 months using PennHip, or would that be a waste of time, if OFA is telling me they are either boarderline, fair, or mild?
Penn Hip gives a % based on comparison in THEIR database to other dog of similar age and the same breed.
They also have notations as to whether you have DJD or not.
You have to make your breeding decisions based on what you are comfortable with regarding your % rating compared to other dogs.
The higher the %, the better the hips, ie, tighter. The lower, the looser...
DJD is a deal breaker of course....
Actually, this is just backwards. The LOWER the Distraction Index (DI) the better. You would like something lower than .30. It really doesn't matter WHERE in the grouping the percentile rating is - that is just a comparison to other dogs that have been evaluated and not to the breed at large or to any "standard" for hips. It is nice for reference, but the DI is the important number in the report. In general, the lower the distraction (degree of laxity) the better the evaluation using the PennHIP format.
A 0.30 distraction index will put the dog in the 90th percentile. That means your dog is better than 90% of the dogs out there. That's a pretty high rating. I would think most people would breed with a DI of anything less than 0.5 (I think 0.46 is average for the breed).
yes... which is why you would LIKE something lower than .30 That is the "break" point used in the PennHIP report - dogs with a DI lower than .30 have very little chance of developing DJD according to their information.
You want a LOW DI and a HIGH percentile rating. The closer each one gets to .50 (or 50%), the higher the risk on developing DJD. I feel really strange relaying information on PennHIP when I don't use it, but didn't want people to get the wrong idea from the post I answered in this thread.
What you get from PennHIP is:
----a DI (distraction index - a number that basically tells you how tight/loose the hips are. It is numerical and based on precise measurements.)
----a percentile (a number telling you what percent your dogs DI falls in. Usually from 10% to 90%. Higher is better. Dogs are compared to ALL dogs of their breed in the PennHIP data base.)
----if there are signs of dysplasia or not
----the PennHIP breeding recommendations. Namely, in order to IMPROVE (as the name suggests, Penn Hip Improvement Program) they suggest you only breed dogs in the top 1/2 of dogs in their data base.
Many, many, many dogs with percentiles in the 30's and 40's obtain OFA Good ratings at 2 years of age. Just keep in mind PennHIP is striving for IMPROVEMENT. That would be obtained by only breeding the best. There is nothing wrong with that goal. However, your average breeder might choose to ignore the recommendations. Even so, you get some serious,useful, quantitive information when you do PennHIP.
Maureen - at DI of 0.50 does NOT correspond to a 50th percentile, at least not anymore. The percentile is something that can and does change as more dogs are in the database as it's the point where 50% of the dogs are above, and 50% are below. Currently (as of a month or two ago), the 50th percentile was at a DI of 0.46.
Reread my post. I said as the DI approaches .50 OR the %le approaches 50% (which is also represented as .50 out of 1.00) the risk becomes greater. I may not use PennHIP, but I do understand the grading system. I just want to know about things other than the DI, so I used OFA I was initially replying to a post that said you wanted a HIGH DI and a LOW %le... which is just the opposite of the desirable readings.
Re: Re: Re: Question about reading PennHip results
Until you have used it for breeding, you don't really
understand the implications of the scoring system. Get
your advice from someone who has used PennHIP to improve
hips.
I used PennHip over 11 years ago on the advice of my orth. vet.. He said it was the new "way to go" and would eventually be what everyone would be using. Well, I have done some PennHip over the years and now always do OFA as well. The problem I had from the very beginning was that not enough people do PennHip for me to be able to have a broad selection of studs to choose from. I now (11 years later) have an opportunity to do both (types of x-rays) on a few 2 year olds that sire and dam (my breeding) have PennHip scores. Honestly, it is more expensive, harder to find studs with scores and I still don't know if it is any better at predicting better hips than OFA. Maybe if PennHip did some marketing or promotions, they could get more involvement and then - find a way to publish the results. Otherwise - it's never going to be very important to do PennHip.
And you wonder why the most of us don't go there. You all use it alot and still seem to question things. It seems to be what you want to make it. I'll stick with OFA.
Re: Re: Re: Question about reading PennHip results
Would someone who has been using PennHip for several generations please explain why the score can go from the 30th percentile to the 70th percentile in 3 months - I don't have the DI numbers in front of me but this did happen to a bitch of mine. Also, another bitch has a score in the 70th percentile and is bilateral Grade 2 - the femoral heads are flattened on both hips and there is thickening of both femoral necks......this has me questioning continuing to do PennHip at all.
I had one dog who I PennHiped at two, his scores on both hips came back terrible, .75 or something like that, according to them he was high risk for developing HD. However there was no evidence of DJD and he came back OFA good. When he was 8 years old he had an injury in one of his back legs and we had him xrayed, they xrayed him in the OFA position and his hips looked perfect, the orthopedist said he had the hips of a much younger dog. So 6 years after PennHip saying my dog was a risk for HD his hips were great.
Re: Re: Re: Re: Question about reading PennHip results
Thanks for sharing this information. There are MANY facets to CHD - laxity is only one. The reason I have not used PennHIP is that I prefer an evaluation of overall hip TYPE, not just degree of laxity. Over the 40 years I have been breeding, there have been several other hip evaluation systems tried that focus on laxity as the ONLY major criterion. Most have been discarded over time because they didn't give the results BREEDERS wanted for selecting matings. PennHIP seems to be firmy ensconced, but the discrepancies between DI readings and actual hip type still are obvious to many who have tried the system.
Just like a breeding program that focuses on only ONE aspect of breed type, hip schemes that focus on only laxity can result in tight hips that do not conform to desirable standards in some other respects. I have found that selecting for many aspects of TYPE - hip and otherwise - usually has better long-term outcomes. That is just my experience over time.
I don't know why you think that I have not seen PennHIP reports. I have reviewed every one that is in LabraData because I do the document entry, so I know precisely what is reported.... and more importantly, what is NOT reported.
Angle of femoral neck is not measured or reported, shape of acetabulum is not noted, etc. There are MANY aspects that are important in a functional and properly conformed hip joint. The shape, and depth of the acetabulum, the length, thickness and angle of the femoral neck, the shape of the femoral head, and many other aspects can vary a lot without any evidence of degerative joint disease. In other words, they are not highly desirable, but they were FORMED that way initially and are not the result of any degeneration. PennHIP has no way of reporting these basic differences - and they are VERY important in selecting what TYPE of hip you want to develop in your breeding line.
A long-time ES friend opted to select her stock based on minimal laxity from about 1960 on. She DID improve her hip statistics (based on what she was selecting to measure) and produced less dysplasia than was prevalent when she started. I opted to select stock based on the other criteria I have mentioned. I ALSO improved my hip statistics (based on what I was selecting to measure) and produced less dysplasia than was prevalent when I started. EITHER system works if you stick with it and I suppose lots of others do as well.
The major difference after 25 years of this type of selection was that I pretty consistently had dogs that OFA certified as good with some excellents and an occasional fair. She pretty consistently had dogs that OFA certified as fair, with some goods and an occasional excellent. Her dogs all had VERY tight hips, but the acetabulae were rather shallow on most. My dogs all had deep hips, but some were rather lax. Again.... BOTH selection processes had value, but by selecting only on laxity, my friend had not developed a line with good-to-excellent overall hip conformation. The overall conformation was not her primary goal and it showed. My goal was an overall quality hip - and it still is.
Maureen, Because you don't understand the statistics that support PennHIP and you have no personal experience using PennHIP as a breeding tool, your comments are purely personal prejudice and should be taken as such
by others.
to switch now - I think that last comment was out of line. I don't think you have to use a system to understand it. I happen to use both PennHip and OFA, but find that PennHip is just not enough for me. As I have commented before, because PennHip is not used by many breeders - it's hard to find studs to breed to that are PennHip. Given that - it has been difficult for me over the past 11 years, to prove to myself that PennHip has great merit. I still use it now and then to see if I can make any conclusions (on my own line) as to whether PennHip is any more useful than OFA. Can't say that I have established that yet.
Again, I do not know why you assume I do not understand statistics. Just because I do not personally use PennHIP does NOT mean I do not understand it. I have spent a good portion of my working life researching scientific topics and distilling their salient features into instructions, descriptions and articles that help untrained readers understand the topic. By both training and experience I have learned to read and evaluate technical material. I understand statistics and the scientific model quite well, which is ONE of the reasons I have opted NOT to use PennHIP.
Your whole statement is dismissive and invalid on its face. Since you ASSUME that I don't understand statistics when I actually do, the rest of your comment is meaningless. If you would like to have a private discussion of the statistics used in some of the PennHIP articles (particularly those self published), I would be eager to do so. One of the articles is so far off target due PRECISELY to the statistical method used that it is not only misleading, it is tantamount to malicious misinformation. I ALWAYS use my name and email address, so you are welcome to post to me about this. We will be addressing the appropriate application of specific ANOVA methods, so bring your statistics textbook along to the discussion
"Of course, you could simply rely on the statistics and research plus time and effort necessary to get better hips using PennHIP."
Hogwash! You don't have to use a hammer a lot to understand how it works and when it is a useful tool for the job. I have invested the time and effort to read the statistics and research until I am very comfortable with my understanding of the PennHIP process. That is why I have opted not to use it for my breeding goals. I do think it is important for everyone to read and try to understand any of the scientific methods we use as tools, whether it is a measure of phenotype or genotype.
I have already stated elsewhere that chosing any rational system of phenotype evaluation as a selection process CAN have the desired outcome of improving offspring evaluations WITHIN THAT SYSTEM. If you select for less laxity in your matings, you will get less laxity over time in the successive generations. If that is your goal, then you can use PennHIP to make progress. That IS a desirable goal, as reduced laxity can also reduce degenerative changes in the bones. That is the very BASIS of the PennHIP method - to reduce the probability of DJD.
The real word that begs for definition here is "better". If your goal is less laxity and reduced risk for DJD, then the outcomes over time using PennHIP will give you "better" hips by your definition. I do not embrace that goal. My preference is to have a well-conformed hip based on many aspects - shape, size, relative angles, approximation of the various bones and processes, etc. in ADDITION to reduced laxity. PennHIP does not provide evaluation of those other aspects of conformation in a way that is useable for me. It will not give me "better" hips by MY definition. OFA does and has for 40 years.
The simple OFA rating system is a distillation of ALL those factors I desire into an overall evaluation. A "good" hip is "good" overall in those various aspects - it does not have serious deviation from the accepted ideal conformation guideline in any of the individual elements. An "excellent" has even less deviation in ALL the aspects evaluated. A "fair" has some deviation in one or more of the elements and it goes down from there. The system does not give particulars in all cases as to the elements that were found to be deviant enough to lower a rating, but OFA has ALWAYS been willing to provide that information to owners by letter or phone.
Since I have chosen to breed for overall hip conformation, I need a tool that gives me feedback on those diverse elements that constitute hip TYPE. Ideally, I would like the BVA system that shows ratings for each of the various elements measured. The only flaw I find with that scheme is that it is entirely based on ONE person's evaluation - an expert, but only one expert. While the OFA reporting method does not provide me with the detail I may want without further inquiry, it DOES offer a consensus opinion of THREE (or four) experts in the field so that the final evaluation is more balanced and useful to me. Clearly, for MY goals it is the right tool for breeding "better" hips.
Maureen, I wish you would restrict your comments to what you know--OFA. You don't know the research about PennHIP, you don't understand the statistics that support it, and you have no experience using it.