Canine Hip Dysplasia - Get the Most Out of Health Testing

Watch the Webinar:

Panelists:

• Cat Matloub, Esq.
• Judi Stella, PhD
• Monica DeBosscher, Esq.
• Christine Liu, Esq.

About Dr. Judi Stella, PhD:

Judi Stella earned her bachelor's degree in Animal Sciences from The Pennsylvania State University and her Ph.D. in Comparative and Veterinary Medicine, with an emphasis on applied ethology and animal welfare science, from The Ohio State University College of Veterinary Medicine. She was a USDA Science Fellow with the APHIS-Center for Animal Welfare and a visiting scholar at Purdue University College of Veterinary Medicine. Her research interests include environmental factors that affect the behavior and welfare of confined animals and the impact of the quality of human-animal interactions on animal welfare. Her research has focused on assessing the behavior and welfare of domestic cats and dogs housed in biomedical laboratories, shelters, veterinary hospitals, and commercial breeding facilities.

About Good Dog:

Good Dog is on a mission to build a better world for our dogs by educating the public and advocating for dog breeders. We are a young, tech-savvy company with an online community that educates the public, supports breeders, helps people connect directly with responsible breeders who have passed our screening and comply with our standards, and promotes responsible dog ownership.

Our goal is to use technology as a force for good and empower the good forces in the dog world with technology – to be a voice and platform for dog breeders, to counter the extremist propaganda, and change the conversation so the public realizes how critical it is to support and recognize breeders. We’re free for breeders (breeders also can’t pay to be listed) and provide support (legal, tech, breeding), and discounts on health testing.

Transcription

Dr. Judi Stella [0:02] Thank you everyone for joining us. We are going to talk about hip dysplasia and periodontal disease. But if we don’t get to periodontal disease, that’s fine, too. Let’s just jump in with hip dysplasia! 

Cat Matloub [0:17] Judi, do you want to give a brief background, a brief intro, for your relevant experience and background on the topic?

Dr. Judi Stella [0:24] Oh! Sure. I have a PhD in comparative veterinary medicine, so I’ve been in vet schools for several years. I did my postdoc at Purdue, and I did my PhD work at Ohio State. Before that, I actually was a vet tech as well, so I was involved with a lot of the repro work that was done there. I’ve actually taken hip films and can speak to that process a little bit. With the periodontal disease, I did a lot of this research into this. When I was a postdoc at Purdue, I worked with a lot of breeding facilities and breeders to help them with periodontal disease, because it is such a significant problem. I’m going to talk a little bit about my research in that area. With the hip dysplasia today, what we’ve been getting a lot of questions about and so what I thought would be good to address, is exactly what you are asking: the differences between PennHIP and OFA and some of the other ones. Why do we get such widely varying screenings done? The results come back quite different. How can we use that screening process, that tool, a little bit better in our programs? That’s really what we’re going to talk about today. 

[1:40] Just to give you guys a little bit of an idea about what the prevalence of hip dysplasia is, it varies widely across breeds. The estimates range anywhere between 1-80% of dogs within a breed could be affected by hip dysplasia. This is just the OFA data, so the top ten breeds based on percentage of dogs that come in contact with abnormal hips, and the bottom ten breeds (the least amount of hip dysplasia). And then I pulled out the ten most popular breeds based on AKC registration in 2019, so the ten most popular breeds based on AKC data. We can see there’s a lot of variation across these breeds, right? So pugs, of the 861 dogs that we have data on, almost 72% come back as dysplastic, whereas if you look at Italian Greyhounds and Chinese Cresteds, the numbers are much lower. But basically this just gives you an idea of how significant the problem is. That’s a lot of dogs. If 12% of all of the Labrador Retrievers being produced are dysplastic, that’s a lot of dogs that are being affected by this, so it’s a significant health problem/health condition, and it can negatively impact the welfare of the dog. Because it’s going to be debilitating and painful. 

[3:06] Symptoms of hip dysplasia include lameness, pain, loss of function in the affected joint and ultimately they’ll get osteoarthritis, which’ll make them even more painful. That’s why we are concerned with this. It is a complex condition, so it’s both polygenic and multifactorial, meaning that there are many genes involved, and there are many factors that affect it. There’s this significant gene by environment interaction, and that interaction results in varying degrees of severity. If you think about the genetic component as being the predisposition for the disease, then how severe it is and when it develops and how quickly it develops is based on those environmental factors, to some extent. The environmental factors that we know impact it are things like injury, so if a puppy has an injury when it is growing, it’s going to be more likely to have these orthopedic conditions. Body condition also will impact it. Obesity increases the risk. We want to keep all of our dogs lean and well-muscled, but especially the puppies. Diet can impact it, especially how diet affects growth rate. The large-breed diets/puppy formulas have been developed because we want to slow down that growth rate and make sure that they grow optimally and not too quickly. And then exercise. Strenuous, high-impact exercise can also increase the risk, so we want to make sure that we monitor that with our growing dogs. And then morphology also will impact it, so large-bodied dogs, brachycephalic dogs, and dogs that have high body length to height ratios, so they’re short-legged and long-backed dogs (like Corgis and Dachshunds)—those dogs are also at higher risk. And then there’s the genetic component. It is polygenic, like I said earlier, so there’s multiple things that are involved in this. And they haven’t been identified, so we can’t really screen for it with a DNA test. It is the most common of the inherited orthopedic traits that are polygenic. So, elbow dysplasia is another one. Luxating patellas is another one. Inheritability estimates for this genetic component vary a lot, from 0.1 to 0.83, so anywhere from 10% to 80% has been estimated as inheritable. A lot of that depends on the methodology, how the researchers went about estimating that and calculating that and also based on the statistical analysis. And then there’s also probably a breed component as well, so different breeds may have different inheritabilities for the condition. So when we talk about screening tests, we can control (as breeders) the environmental factors. We know what they are, and we can control for those. Morphology, we can control to some extent by breeding to breed standard or modifying the breed standard where we need to. When we talk about screening tests, what we want to focus on is that genetic component and trying to decrease that genetic component to the extent possible. 

[6:15] When we talk about minimizing risk, we’re talking about minimizing the risk of the genetic component. That is going to be based on the selection of our breeding dogs. There’s this old adage in horse racing—I don’t know if anybody is a horse person. But you breed the best to the best and hope for the best. The idea is that we need to identify who the best are, which are the best dogs. We do know these breeding strategies; if we incorporate these screening processes into our breeding strategies, they have been successful. They’ve been shown to be successful. There have been individual breeds or breed clubs in specific countries that have really, really focused intensely on this, and they have made pretty significant changes. One example of that is the Kooiker. (I’m probably mispronouncing that.) It’s a European hunting dog. After World War II, there was this genetic bottleneck, just because of the war; there weren’t that many dogs left. When they started breeding them again, there was a really high prevalence of luxating patellas. They’re hunting dogs. That was impacting their ability to do the work that they were bred for, so breeders got together, and they really focused on this. Over several generations, they decreased the prevalence from 28% to 19%. It’s still relatively high, but that’s a significant decrease. So it can be done. A recent study just came out earlier this year. James et al. found similar declines in hip and elbow dysplasia in the last 30 years in six breeds in the UK: Labrador and Golden Retrievers, German Shepherds, Rottweilers, Bernese Mountain Dogs, and Newfoundlands. Big dogs that have a lot of hip and elbow dysplasia. Again, they focused on it in those populations. They actually got significant declines in that. We just need to have better ways to effectively identify these. Historically, what we’ve been doing when we make breeding decisions, is we’re basing it on the phenotype of the individual. So we take hip X-rays. We just ask: Does the bitch have good hips? Does the stud dog have good hips? We put them together and hope that the puppies will have good hips. It hasn’t been as successful as we would like it to be. As we all know, it doesn’t always work out that way, right? You can have these excellent hip parents and still wind up with puppies that have hip dysplasia. One thing that’s come up recently is this estimated breeding value. There’s a group at Cornell that has been working on this. What they’re doing is trying to integrate that genetic and phenotypic information into a calculation that you can make to try to have a better predictive value to the breeding decisions. What they’re saying is that every dog has a breeding value, that there is breeding potential for every trait that you want to pick. The research has been focused on elbow dysplasia and hip dysplasia. But, in theory, you could do this with anything. If you base your breeding matches on evaluation of the trait in the dog as well as in several relatives (as many relatives as you have information or data on), statistically, that will be more predictive of the offspring, the traits in the offspring, the phenotype of the offspring. Basically, if you put information in about all of the relatives, and you put it into this little calculator and calculate it, it will be able to tell you better what the offspring’s risk for hip dysplasia is. Like I said, it can be true of any trait. Input the information. 

[10:10] Just to show you how this plays out, this is data from this group. This is Hou et al. Again, based in Cornell. They calculated the estimated breeding values. They used the whole OFA data set. They calculated these estimated breeding values for hip and elbow dysplasia in 74 breeds from the database, from 1971 to 2009, so about 40 years. They included any breed that had data on more than 1,000 dogs. They excluded any chondro dysplastic dogs or breeds because they think that the genetics of hip and elbow dysplasia in those breeds is different than in non-chrondro dysplastic breeds. The dogs were all screened between 24 and 60 months of age. Mind you, this is the estimated breeding value here on the Y Axis, and not all of these axes are the same. They’re a little bit different. But you get the idea. In St. Bernards, which is one of those breeds that is in the top ten prevalence of hip dysplasia, it seems to be going up over the course of those years, where in Labradors, we’ve made a lot of progress, and it’s coming down. 

[11:35] German Shorthaired Pointers is one of those top ten popular breeds. About 3.9% have hip dysplasia, according to OFA. You can see this huge decline in the estimated breeding value in these dogs. German Shepherds are up and down a little bit. 

[11:52] Golden Retrievers, same thing—up and down a little bit. Rottweilers, not much change. It’s coming down a little bit in the last 20 years or so, but not a whole lot of change. 

Cat Matloub [12:04] Judi, we have a couple of questions. I don’t know if you can see them, since you’re presenting. Do you want us to ask them now, or do you want to keep going? Can you see them?

Dr. Judi Stella [12:12] It’s up to you! Is it related to these things? Or we can wait until the end of the hip dysplasia part. Whatever you guys want! 

Cat Matloub [12:18] Perfect. Just wanted to flag for you, because I know when you’re presenting, it can be hard to see. So at the end of the hip dysplasia part, we’ll ask these questions. Thank you!

Dr. Judi Stella [12:28] Cornell does have this tool, so you can go into Cornell and any of the dogs—I’m pretty sure that it’s only based on dogs that are in the OFA database—you can plug in any information (the registered number) that you have on as many relatives as you have and what it’ll do is tell you what the offspring’s estimated breeding value is. It’ll tell you, based on the breed average, where that match the offspring will fall. If the breed average is here (0.08), it’ll tell you what the risk is. Are you decreasing or increasing the risk? It just sort of helps you make those breeding decisions a little bit better than just basing it on the two breeding dogs (the sire and the dam). BVA, the British Veterinary Association, also has a tool that’s very similar. It’s called Mate Select. 

[13:26] The one caveat to that tool that Cornell has is the data that comes out, the results that come out, are only as good as the data that comes in. So, if we don’t register all of our results for the hip screenings for the breeds, then it’s going to be this biased data. Those results and those estimated breeding values won’t be as valuable. To that point, this study was published in 2005. They look at exactly that. They were trying to look at the true prevalence of hip dysplasia in just two breeds (Goldens and Rottweilers) and then compare it to what’s in the OFA database, essentially. What they did was they took dogs that were presenting for hip evaluation. All these dogs are clinically normal, meaning they weren’t coming in because they had hip pain or they weren’t limping or anything like that. They were normal dogs. They came in, they did a hip evaluation or a hip film, on 200 Golden Retrievers, 140 Rottweilers. Then they compared them. They also did another group that was 93 dogs that came in specifically for OFA hip films. What they found was that the prevalence of hip dysplasia was 53-73% in Goldens and 41-69% in Rottweilers. If you remember from that beginning slide, OFA database says that about 19.8% of Golden Retrievers and 21.2% of Rottweilers have hip dysplasia. These are much different numbers. When they looked at the submissions to OFA, of the 93 dogs that came in to have their hip films taken specifically to send to OFA, 49 of them were submitted. So there was only a 53% submission rate. Of those 49, 45 of them were normal. So, 90% were normal. What they concluded when they calculated this—it was 8.2x more likely that the films would be submitted if they were normal than if they were abnormal. Interestingly, the Rottweilers breeders were more likely to submit the films than the Golden Retriever breeders. They concluded that the prevalence of hip dysplasia may be much higher than what we understand it to be, because we’re pretty much basing it off of that OFA database, because that’s the only data that we have. The estimated prevalence is likely a lot lower than the true prevalence. This just sort of is to point out why we think registering these results in a database is so important. We can make sure that we have all of that data and make better breeding decisions. 

[16:13] Now a little bit about the different screening registries and how they go about it, what the differences are, and the pros and cons to them. These are the three common ones in North America. OFA uses one X-ray view, which is the VD (ventrodorsal). The dog gets laid on its back, they pull their legs out in an extended position, and take the X-ray. There’s no special training required. Your rDVM can do it. Chemical restraint is recommended, so either anesthesia or sedation, but it’s not required. One little note on chemical restraint; I would urge all of you to consider using that when you do that. It is a less fearful experience for the dogs. They’re laying on their back, and pulling on their legs. They often have to be muzzled because they are scared and they’re big dogs and the technician has to get down in their face. It can be pretty fearful for them. It’s much easier to position them when they’re sedated, which means you’re likely to get a better positioning and a better X-ray to submit to OFA. It also results in fewer X-rays. You don’t need as many, so there’s less radiation exposure for your dog. Really, anesthesia and sedation are pretty safe for young, healthy dogs. I would urge all of you to talk to your veterinarians about that and really consider doing it. They do scale these, as well know. Excellent to severe dysplasia. It’s a 7-point scale. They do have that borderline where it’s not really clear whether it falls into either of the other categories. There are three board-certified radiologists who independently review and score the films, and they use 9 anatomic areas that are assessed on the hips. The concordance rates have been reported to be about 74%. Of the more than 1.8 million films that have been submitted to OFA, about 75% of the time, the radiologists agree, which is what that concordance rate means. That’s pretty good, but that means that about 26% of the time, they don’t agree. I don’t know what they do with those. I honestly couldn’t find—I mean, I could call them and ask them. If three of them agree 70% of the time, 2 of them agree 20% of the time—it’s unlikely that there’s much difference going on there, and I’m sure they have a way to figure that out. And all the dogs must be over 24 months of age. 

eVet is another way that we can get these assessed. They use the same one X-ray view, VD-extended. The rDVM can take the X-ray. I don’t know about chemical restraint. I didn’t find any information about that from them. I believe that they leave it up to the attending veterinarian that’s taking the films to decide whether or not to use that. They use OFA’s scale and grading system. One of the differences is that they only have one board-certified radiologist to do it, rather than three. And there’s no minimum age for the dogs to have these films taken. They leave it up to the discretion of the veterinarian. I would caution you on using this one. I would use this as a preliminary exam kind of thing, if you’re going to use eVet. The redundancy built into having three board-certified radiologists look at it versus one actually gives you a more robust measure of the dysplasia, if the dog’s dysplastic. And not having any minimum age here… I know that OFA Dr. Hutchinson actually addresses this a little bit in a webinar he did for us. OFA used to allow hip films to be submitted at 18 months of age, and they no longer do, and that’s because the results weren’t as predictive. The screening wasn’t as robust or as good when they screened them at 18 months versus 24 months of age. If you’re going to use the same scaling system, they probably should do it the same way and make sure that the dogs are 24 months of age. If you’re doing this, it’s just probably a little less robust, and I would make sure that the dogs are 24 months of age before you submit them. 

Now, PennHIP is completely different. It’s a completely different system. They use three X-ray views (extension, compression, and distraction; three different views of the hip). Chemical restraint is required. Training for either the technician or the veterinarian that are taking the film is required as well. It’s free to veterinarians that want to do it, but you do have to find a veterinarian that is certified to take these. They use a distraction index to measure it. It ranges from 0 to 1. The higher the number, the closer you are to 1, the more lax those hips are. The more lax the hips are, the more likely the dog is going to be dysplastic. Their cut-off is they want to see most of the dogs below 0.3. Then they think the hips are tight enough, and the dog shouldn’t have any problems. The interesting thing here is that each dog is ranked within its breed, so it’s ranked against the mean of that breed. So you know where your dog falls, relative to all the other dogs. The dogs can be scored and screened at 16 weeks of age. That’s kind of a bonus, if you don’t want to keep your dog around and provide all the resources and money that it takes to raise a dog till two years, because you can screen them early and rehome them, if that’s something that you’re thinking about doing. 

[22:07] A little more about OFA/PennHIP. OFA evaluations are qualitative; the PennHIP evaluations are quantitative. Quantitative evaluations (quantitative measurements) tend to be less subjective, so if you want to remove as much subjectivity as possible, and you want to go with a more quantitative assessment, PennHIP reports the results relative to the other dogs in your breed. The reported means (the means for each breed) are available to the public. They include all the dogs that they screen. That’s a little bit different than OFA because with OFA, you have to opt in, right? You have to submit your bad hip films, and a lot of people don’t do that. OFA evals are easier to “pass.” They’re less expensive, and they’re easier to access because veterinarians can do those films. Another thing that’s different and that you need to look into a little bit is some breed clubs require OFA is used and won’t allow some of these other registries. There’s pros and cons to each. OFA has a bigger database, so if we want to look at the data and do these kinds of estimated breeding values and things like that, then that’s helpful. It just depends on what you are looking for in your evaluations. There was a study done that actually compared scores in the same dog. They submitted hip films to OFA, and they submitted hip films to PennHIP and did both of them. What they found was that 4% of dogs were scored as excellent for OFA and, of those, 52% didn’t meet that requirement of 0.3 or lower, so 31 of those dogs were above that 0.3. It kept going. So by the time you get down to fair to excellent—if you take all the dogs from fair to excellent (so everybody that would pass OFA and be rated as normal)—80% of those dogs had a DI that was greater than 0.3, so only 20% of them were in agreement. Only 20% of the dogs pass both OFA and PennHIP, essentially. But on the reverse end, it was 100% agreement, so if the dogs were borderline or worse by OFA, they all had a score of greater than 0.3. It looks like PennHIP and OFA agree on the bad end. They both can identify dysplastic dogs, but the good end tends to be a little bit more disagreement. And then there was this other study by Smith et al. They looked at the same sort of thing, and they concluded that the OFA criteria were more influenced by diet and age (so, environmental factors), where the DI measurements were not. What they concluded was that the DI measurements (or the PennHIP scoring system) actually was pulling out the inheritability (the genetic components) of the hip dysplasia. If we want to get rid of that genetic component, it looks like there’s pretty good evidence that the PennHIP may be a little bit better. 

[25:56] And then just to show you: this is that first slide again that had the prevalence, the percentage of dogs for OFA, and then I just also added in the distraction indexes. It kind of shows that exact thing. So, see we have a high percentage of dogs that are scoring dysplastic by OFA. You have a high DI, but then if you look over here, you have 12% of Labradors but 0.49 is the new DI, so you get this discrepancy on that positive end. 

[26:36] And then just real quick: there’s other registries that people use. They’re mostly European, so BVA: They also use the same one, VD view. Regular rDVM. They do require chemical restraint, and that is due to safety around the veterinary care staff. Over there, you can’t physically restrain animals for X-rays except when it’s an emergency, so they require that the dog have chemical restraint so the care stuff can be out of the room and not get that radiation exposure. Same nine features on the hip assessed. They score them a little different: 0 to 53 on each hip, and then you get a total score of 0 to 106. The higher the number, the worse the hips are. They’re only independently reviewed by two board-certified radiologists or orthopedists. And the dogs have to be more than 12 months of age. 

FCI: They do it with one view, the VD, but they actually recommend doing two views. It optimizes the scoring. They require chemical restraint as well. It’s a little bit different because they include a quantitative and a qualitative element. This Norberg angle is the quantitative element, but then they also have the subjective scoring of the hips, which is the qualitative element. They only have one specialist review, and that specialist has to be approved by the breed club. Dogs must be over 12 months of age, and for large breeds, 18 months of age. 

And then SV is the German equivalent. It’s all in German, their instructions. I can pull out more information for anybody that’s interested, but it’s pretty similar. Same view, months of age, and I think chemical restraint is required from them as well. 

[28:27] So that is all I have for hip dysplasia. We can take questions now and have a little discussion. 

Monica DeBosscher [28:40] So Amanda said that she’s a fan of PennHIP because she feels like they can see if they’re improving the breed in this area. 

Dr. Judi Stella [28:48] And it is, because you can really see where your dog is, relative to all the other dogs that have been scored. We don’t really have that with OFA. You can’t really see that. If the Distraction Index is really high in a breed, it allows you a path to make that better, right? Even if the Distraction Index is 0.7, if your dog is 0.65, then you’re headed in the right direction, right? You can kind of monitor it a little bit easier I think. 

Cat Matloub [29:33] There’s a bunch of questions. I’ll just start from the top. Patricia wrote in to ask: How does the PennHIP score of D1 or DLL 0.36 and DIR 0.38 translate into OFA categories? If it translates as good, is there any way of knowing if it is closer to excellent or fair on the scale?

Dr. Judi Stella [30:01] A 0.3 is their cutoff, right? So, they say everything less than 0.3. I actually think on the OFA website, they have a little table that says if you have an FCI this, it equals this in OFA. I think because PennHIP is so much different than OFA, I’m not sure that they’re super comparable. I can go back and look at that, though. If you guys flag those questions, I can go back and see if I can dig up more information on that. Like a 0.36 would be really good because anything less than a 0.3 would probably be like an excellent. 

Cat Matloub [30:47] Awesome. Terry asks: In Welsh Springers, my vet has noted that they tend to not have loss of fluid due to less or no damage to the fluid capsule. Is that something that you know anything about?

Dr. Judi Stella [31:00] No. Sorry, I don’t! 

Cat Matloub [31:05] Thank you, Terry. Interesting to know. Micky asks why do some dogs with failing hips and/or elbows have no lameness whatsoever?

Dr. Judi Stella [31:17] Most dogs that are going to be dysplastic are going to get painful at some point in time, but it may take till they’re older. If you keep them lean, if you’ve got lots of muscle around that joint so that you are keeping it more stable, that will help. And then it just depends on the degree of osteoarthritis. You can have a mildly dysplastic dog that might not ever show that much pain because you manage it, you manage their environment, and all these other things. Severe hip dysplasia—those dogs are going to be painful. All dogs are different. Some dogs are really stoic, right? And they’re just not going to show that much pain. I don’t know. I think it’s going to be very individual-specific. I’ve never seen a dog that has severe hip dysplasia where the ball and socket are really grinding together and rubbing together—those are going to be painful. It probably just has to do with severity of the disease. 

Cat Matloub [32:25] In a conversation around whether or not it’s required to list the results… There’s a comment from Charlotte: OFA will do prelims with only one radiologist on dogs at 4 months to 23 months, correct? Only a letter, not a registry number, given, and it’s not seen on a public database unless signed off on by the owner, correct? And then Lisa (hi, Lisa!) chimed in with: With PennHIP, I believe the films have to be submitted. The owner cannot choose to send if they do not look good. Teresa says: When will PennHIP allow their information to the public so breeders can use the information?

Dr. Judi Stella [33:15] I don’t know! They don’t allow it to the public. They really don’t. You can’t look up an individual dog, but if somebody gives you the results, you can compare it with the mean for the breed. You can put it into that relative context. PennHIP does do that. That mean for the breed is the mean for the breed. Every single dog that gets this done—it’s included. That makes it more robust, honestly. And I honestly have no idea why they don’t make that database available. It would be really nice if they did. It would be good from a research perspective. 

Cat Matloub [33:53] And a whole bunch of other things. I wonder if we could ask Dr. Serpell. 

Dr. Judi Stella [33:57] PennHIP, they developed it, but I think now it’s in a private company. Because you have to go through ANTECH—that’s who you submit the films to. 

Cat Matloub [34:08] I see, I see. Claire said: I did use eVet as preliminary for my sire, and he was sedated. For my dam, with OFA I was allowed to be in the room at her head, so no muzzle or sedation required. Considering PennHIP for my sire, offspring, and potentially including my dam also. This is going back to some of the specifics, some of the stats. Someone asked: Why do they think it’s higher in brachy breeds? 

Dr. Judi Stella [34:59] You know, it’s interesting. I don’t know that it has anything to do with the brachycephalic. I think it probably has to do with the chondrodysplasia. Those dogs, I think they’re chondrodysplastic, too. If you think about a bulldog, they have the shortened legs and all of those different things that go along with the brachycephalic. I don’t know that it has to do with that as much. It’s interesting because boxers—they’re brachycephalic, but they don’t tend to have as much hip dysplasia, so there’s something else going on, and it may just be that the genes that are associated with brachycephaly make them more predisposed. 

Cat Matloub [35:46] Na, commenting on statistics, has a rare breed, so unfortunately, this dog has to be compared to all breeds due to lack of data. That’s maybe something that we can also help with, too. Shoot Judi an email, because when it comes to trying to gather research and all of that, we are hoping to be an even greater resource. Definitely do reach out to Judi. Yes, Micky points out the problem with PennHIP is that it’s not a published database. 

Dr. Judi Stella [36:25] They’re not a published database, but one of the things that we have been talking about internally at Good Dog—one of the things that we would like to do—is start collecting data from our breeders, so if we get to a critical mass, we would have a good database of our own. 

Cat Matloub [36:46] Definitely. There’s a comment from Dawn, trying to compare OFA results with PennHIP, and she says: I have a friend whose dog came back dysplastic from OFA but got a score of 70% better than the breed in PennHIP. I’ve always tried to understand this, as I’ve heard of dogs that pass OFA try PennHIP because it will score better than others in the breed due to the number of OFA dysplastics going to PennHIP. I see. You’re getting a filtered group of people who are going to PennHIP. When people get OFA dysplastic, and then PennHIP, they’re going to. It’s more expensive, but it could potentially allow them to give them a different result that could breed the dog, right? So it’s kind of like a feud.

Dr. Judi Stella [37:35] Yeah, but that’s interesting because the studies show that if it’s dysplastic on OFA, it tends to agree. At that bad end, PennHIP and OFA tend to agree more than on the good end. If you got good hip and excellent hip film in OFA, it’s less likely that you’ll pass PennHIPP, right? It doesn’t agree as much as it does on the bad end. So, failing OFA and then going to PennHIP—it’s interesting that that’s happening because it shouldn’t work that way, based on the data that I’ve seen. 

Cat Matloub [38:14] Probably just anecdotal. It stands out as something you hear, right? Like, oh my gosh, I got a bad OFA result, but then I went to PennHIP—

Dr. Judi Stella [38:22] It also just could be positioning, too, right? You’re measuring different things. If you look at some of the data, that last study where they’re saying the OFA is assessing more the environment factors where PennHIP is more the genetic ones (because they’re looking at that confirmation, how tight that ball and socket joint is). So OFA may be looking at remodeling, which is that osteoarthritis, so you might just be measuring different things. It is interesting. 

Cat Matloub [38:57] This is a good question. Judi, from Fonda: How would I explain PennHIP results to a potential puppy buyer who understands OFA but does not know about PennHIP?

Dr. Judi Stella [39:11] We’re actually working on that! That’s one of our documents that we’re working on to try to get you information on that. Again, basically it’s quantitative so you’re measuring the tightness of that ball and socket joint. That’s what that Distraction Index is, and those three different X-ray views are looking at that. But you’re really looking at how tight that ball and socket is. And then that Distraction Index is measured against other dogs in the breed. You can show them: your dog is a 0.3; the breed average is 0.35, so your dogs are better. It seems to be a little bit more predictive of whether or not those dogs are going to get hip dysplasia. OFA is looking at sort of the same thing, because they’re looking at how that ball and socket fits into the joint, but they’re also looking at the modeling. So they’re looking to see if there’s any actual arthritis. 

Cat Matloub [40:11] Could you (one more time) go through what does a 0.3 number mean? Kate hasn’t used PennHIP. Is passing based on 0.3 or the mean for the breed? If the mean changes, how does that affect a dog who already passed? 

Dr. Judi Stella [40:29] They don’t really give pass/fail. They’re just trying to say, “This is the mean Distraction Index.” The 0.3 (my understanding of it, and I can look into this a little bit) is if it’s above 0.3, more likely they’re at increased risk for getting hip dysplasia. If they’re less than 0.3, they’re at decreased risk for getting hip dysplasia. So that’s at the individual basis. The reason that you’re putting it into the context of the breed mean is you want to look for if the mean is changing. That 0.3—your dog is still going to be at increased or decreased risk. If the mean for the breed changes, your dog at 0.3—if the breed mean goes down to 0.2—it’s not as good. But still, the risk for hip dysplasia is still going to be exactly the same. So they’re not looking at it as a pass/fail kind of thing. It’s just a relative measure. Does that make sense? Monica, did that make sense? 

Cat Matloub [41:33] Yeah. So the mean of your breed is unrelated to the score that you will get from PennHIP. It’s just a good guide for you to use to help inform decisions as you’re looking at the results that are centered around this 0.3, which seems based in science, above my pay grade and knowledge of where that comes from, but that’s the important way of how they measure it.

Dr. Judi Stella [41:58] It’s a calculation based on all the measures that they do on those three different hip films. So there’s a whole system for how they do it. 

Cat Matloub [42:10] We have a question coming from Sherry: There was a recent article discussing a whelping environment and the risk of HD based on these conditions. Some environmental factors are to be considered, but can you elaborate more on flooring when raising puppies? I want to be able to inform any new owners what the current recommendations are. 

Dr. Judi Stella [42:30] What I can tell you is you don’t want them to be on slippery flooring. That’s always been a thing that I’ve understood. I don’t think there’s any real good data or studies around the type of flooring and risk for hip dysplasia. But when I worked in the kennels, we talked a lot about flooring. They had these slick floors because they needed to be able to sanitize them, and then they’d put shavings on top, and they were very slippery for the puppies to be able to stand on. So, lots of natural flooring substrates. Some of those rubber mats that you can get that are like puzzle pieces and things for little kids to sit on the floor—those types of mats can be good. You just want non-slip, and you want to make sure that they don’t get their little toes in loops of rugs or towels and things like that. Obviously, not too hard. And then from a socialization standpoint, you want to make sure that they have access to lots of substrates, so I would encourage that as well. I will have to look into that. If you can point me in the direction of that paper—I don’t think I’ve seen that, and I would like to look at it. I don’t know of any real good data looking at associations between types of flooring.

Cat Matloub [43:54] From Patricia: Would you discuss the importance of scheduling intact females to be tested midway between predicted seasons in order to avoid hormonally affected joint laxity? 

Dr. Judi Stella [44:10] That’s a good point. You don’t want to do films when they’re in season, when they’re pregnant, or obviously right after they finish weaning puppies. You do want to make sure that they are as equidistant from weaning and the next cycle as you can. The relaxant that is associated with all the hormones and everything does loosen up the hips that causes that laxity, and it will change the results. That’s also true of luxating patellas, if you’re looking at that, too—it definitely will do that. I don’t know that there’s an exact two-weeks-after-weaning or anything like that. I think if you wait a month or two after you wean a litter, you probably will be okay. 

Cat Matloub [45:02] Super. So we’ve got a couple of folks still trying to figure out what the best test to use is and how to explain that and the results to puppy buyers. As Judi said, we are putting together information and educational materials around exactly this to help you understand the results and help you be able to explain them to puppy buyers. 

Dr. Judi Stella [45:33] I think it’s hard to say what is the best and what isn’t, because there are pros and cons to each, right? If you don’t have access to a veterinarian that can do PennHIP, then by all means, do OFA. Understand that if you got a good score, good hips—they may not be as good as that. But if you’re going to do OFA (and that might be because your breed club only accepts OFAs or whatever, for whatever reason you decide to do it), then use those results with the estimated breeding value. Put them into that calculator and use that tool as well. I don’t know that we can definitively say, “This is good. This is bad.” My preference—but this is only because I’m a data person—is for PennHIP because it’s quantitative. I hear so many stories that OFA is just somebody’s opinion. Well, yes and no. That redundancy in having three board-certified radiologists look at the hips—they do have a systematic way of reviewing them and those types of things. It’s 74% concordance rate or agreement between those specialists. That’s pretty good. You’re not going to get that in a lot of other assessments. I don’t think that the OFA is terrible. You can see with those graphs, when we really start to focus on it and the whole breed (everyone that’s breeding these dogs) focuses on it, you can make improvements in the breed. I just think we need to weigh the cost/benefit of each of them, with the breed, and then make a decision and stick with it. 

Cat Matloub [47:25] Charlotte has a couple of comments. Charlotte is the Health Chair for her breed parent club. Amazing. That’s so cool. Dogs in Europe are using other methods there? Judi and some of our advisors and partners and experts have talked about the fact that generally, with respect to some of this testing, there’s a lot of exciting research going on in terms of trying to find ones that are more reliable and accurate and isn’t a weighing of pros and cons. But I’m curious, Charlotte, if there was anything you were talking about specifically. She notes that OFA says that HD generally do not show remodeling on hips, even if done on older dogs. Puzzled as to whether the method is not appropriate for breed. She’s asking if you know if there are any studies pending for dwarf dogs. 

Dr. Judi Stella [48:28] No! I don’t, actually, but that’s an interesting question. 

Cat Matloub [48:35] Someone chiming in saying they would much recommend the rubber mats. Address differences in positioning from one vet to another and the associated result differences that can result from a vet’s proficiency or lack thereof (question from Patricia).

Dr. Judi Stella [48:54] One hundred percent that is definitely true. They have to be more or less perfect. It’s really hard to do. Again, speaking from experience (because I did), you put them on their back and you put them in a positioner, so sometimes it depends on even just the type of dog that you have. If you’re putting some little, really narrow sighthound into the positioning tray, they tend to rock back and forth on their spine, and it becomes very difficult to keep them straight. How you position those legs and how straight you pull them—it really can impact how they view them and what scores come back. If their pelvis is tilted, it becomes difficult for them to measure some things. To the extent possible, I would try to find a veterinarian that is experienced that does do hip films. Anybody can do this VD view. We do it for all kinds of other things (for abdomen films and chest films), but this particular positioning does need to be done well, and it will change your results for sure. 

Cat Matloub [50:09] Teresa asks: Is there an advantage to doing both? Specifically does PennHIP and then has films sent to OFA as well, but she’s not sure if she’s just wasting money.

Dr. Judi Stella [50:22] I don’t know. It doesn’t look like they agree. Again, if you look at the studies on the bad end… Here’s what I would say. If you want to do OFA first, because it’s easier and because it’s less expensive, you could do OFA. If they come back as borderline or worse, it’s likely true that that dog just doesn’t have good hips. On the other end of it, if they come back as excellent, good, or fair, then if you really want to know for sure, then I would do PennHIP. Does that make sense? You get more reliable results that way with PennHIP. 

Cat Matloub [51:10] Charlotte, with respect to dwarf breeds—she knows that [51:20] Terrier often are labeled as having hip dysplasia but have never been crippled, even in their teens. Judi, I’m curious to hear your answer. 

Dr. Judi Stella [51:34] I wonder if that’s why we don’t do it with Brussels Griffons too. They’re small, little dogs. I’ve never heard of one having hip dysplasia. Maybe the conformation isn’t correct, but it doesn’t actually impact them in any way. I actually had this discussion with a Frenchie breeder. I don’t know if this is true—and any Frenchie breeders out there, please tell me—but they said that even though the dogs tend to conformationally come back as dysplastic and it’s really high prevalence in the breed, that they tend not to have osteoarthritis and be lame. So there may just be breeds where it’s not a good test. Maybe we just don’t need to worry about it in certain breeds. But I don’t have enough information, honestly, to know. Because we don’t know what the true prevalence is and unless we know how many French Bulldogs out there in the general population have been diagnosed with hip dysplasia and are painful, we can’t really answer that question. 

Cat Matloub [52:30] It is interesting, just purely hypothetically, to think about dogs that have shorter legs so they’re not dealing with potentially so much weight that’s coming down with gravity at such an angle—so even if the joint is a little loose, it takes a threshold amount of weight to cause that to be a problem. It’s a really interesting question. For the purposes of data, in our community, that’s easily something that we can just start getting data on. Following up, sending surveys to our breeders, reaching out, figuring out what we’re actually seeing, working with vets, and all of that. What great insights that could potentially have in the breeds that they might test dysplastic for but that may not show any negative effects. Potential insights into how to help the breeds that are showing the negative effects. 

Dr. Judi Stella [53:29] It’s definitely an interesting conversation. Again, we’re trying to weed out that genetic predisposition to the extent possible, but if 70% of Bulldogs are coming back dysplastic, clearly you’re going to have to breed some of them, right? You can work to decrease it. If it’s not a problem in those breeds— but I don’t know that it is. We would love to do this kind of research and start filing these dogs up. Because honestly, if it’s not a problem, then stop worrying about it and let's put money into screening for something that is a problem, rather than have all of you do screening tests that mean nothing, that are just meaningless as far as the dog’s wellbeing is concerned. 

Cat Matloub [54:12] We’re so well situated to be able to look at that as well, given our large community of puppy buyers. We can keep track of the dogs and help with that. Awesome, awesome! A couple of things. One thing to note, there was a request for a link to the Cornell EBV calculator. We’ll send that out to all of you. I don’t have it handy, but we’ll get it in an email to you with a recording of this webinar as well. One last comment I just saw was: At what age can you get PennHIP done? That’s at two. If anybody has any questions at all, or any questions that we didn’t get to or missed somehow (and I apologize if we did), then please just shoot us an email, and we would be more than happy to chat with you or get you a response over email, or whatever we can do to help you out. Thank you all so, so much. Stay tuned. We’ll be following up (hopefully very, very soon) with more of those informational guides and education for both your reference as well as for sharing with puppy buyers on OFA and PennHIP. Thanks, everybody, so much for your time! Really appreciate it. Have a wonderful afternoon and a wonderful weekend! Bye, guys!