Hip Dysplasia statistics – a first glance

As my last post stated, I have spent several months on going through and isolating the statistics for “Field Goldens” (or “working golden”, or “jaktgoldens”) from 2010 and up until today. I also promised to write about my findings in coming post. So, let’s start digging into the analysis of all the figures I have gathered!

In this first post I will look into the high level statistics of Hip Dysplasia and compare it to the statistics of the overall breed statistics. But before doing so, I want to remind you of that I am doing this first and foremost to learn myself and I will NOT be naming any breeder, dog or dog owner when presenting my statistics. Also, if you are curious about which breeders are included in my research, you can find the complete list in my last post, which you find here:

https://flickerinflames.wordpress.com/2018/02/08/a-small-big-project-field-goldens-2010-2017/

Again – if you think I have missed any breeder or if you are a breeder and believe you should be part of the statistics – let me know. I will gladly update and improve my statistics. Okay, brace yourselves – it’s a lot of facts and figures.

Here we go :)!

The Swedish Kennel Club and overall strategy on Hip Dysplasia

As a part of their general breeding policy, the Swedish Kennel Club states that it shall “contribute to the creation of breed-specific breeding strategies as well as prioritize breeding that benefits the offspring’s probability to a long life without health problems.” Exactly how the Kennel Club is really doing the prioritization of certain breeding is unclear and deserves further investigation. When it comes to hip dysplasia (from now on referred to as HD) it is specifically mentioned in one the so called “Basic Rules” of the Swedish Kennel Club, where you can read the following:

SKK Basic Rule 2:2
When it comes to hip dysplasia, it is not considered compatible with paragraph 2: 2 to use dog with HD grade E in breeding, nor to breed a dog with HD grade D with other than a dog graded as A or B alternatively in a combination where HD index is greater than 100. Whatever HD grade, it is incompatible with the basic rule to use dogs with any clinical symptoms of HD in breeding.

Yes, you read that right. If you can find a dog with a really high HD index so your litter index goes over 100, you are allowed to use a dog with HD grade D. I wonder how that fits with the sentence they have in their general breeding strategy. The only reason I can see to use a dog with D-hips is if the breed is really small and it’s a matter of saving the breed. And if that was the case, SKK could handle that as an exception instead of having it as a basic rule for all breeds. At least, that’s my view on it.

The Golden Retriever Club and the “Breed specific strategy”

The breed-specific strategies (“RAS – Rasspecifik AvelsStrategi”) are created by the breed clubs, which are sub organizations to the Swedish Kennel Club itself, so in our case the strategy is created by the Golden Retriever Club (or in Swedish it’s called “Goldenklubben). The last two years I have tried to get a hold of the strategy from the Golden Retriever Club. Last year they “were running late” and this year it is bureaucracy delaying the approval of the new strategy. So, currently Golden breeders have no real strategy to adhere to so we all have to rely on the old one, which was valid from 2012 to 2016. I have complained twice about this in rather harsh words and offered my help and support in setting the new strategy at least once.

Anyway, in that old strategy, there was a few breed specific goals related to HD, which we, as breeders, are supposed to work towards together. And it is those against those goals I would like to do my first analysis.

Goal 1: 65 percent of dogs over two years to have known hip and elbow status

The first goal is that at least 65 percent of dogs over two years shall have taken x-rays of both hips and elbows and hence have known hip and elbow status. Depending on how you measure that, you will get different figures. Looking at the way the Golden retriever Club is measuring it seems they are comparing the amount of born puppies to the amount of x-rayed dogs in a year. The reason I believe they do so, is that in their evaluation in the Breed Strategy 2012-2016, they use a table from SKK Avelsdata (a database provided by the Swedish Kennel Club). That means they are assuming that the same amount of puppies are being born from year to year. If we follow that way of evaluating how many have had dog’s hips and elbow x-rayed and look into SKK Avelsdata for 2010-2015, it looks like this:

hela_rasen_rontgade

I don’t know how they measure the percentage of dogs having their x-ray done before 2 years of age, but as the average of the breed in total is 16 months – it is fair to assume that out of the dogs who HAD their x-ray done the majority was below 24 months.

However the goal of having 65% of the dogs x-rayed has failed on a total level. Actually, the average during 2010-2015 is only 55%. That means that just above every second dog is having their x-ray done.

Let’s see how it looks if we break out the Field Goldens born 2010-2015. Be aware that in my statistics, I have looked into each litter and seen how many of the dogs BORN in a certain year was x-rayed at all. From now on, I will only include dogs who had their x-ray done before turning 3 years old (meaning I will look into the litters of 2015 when 2018 is over). So when my figure says that for example in 2010, 168 puppies were born and 128 were x-rayed, it really means that. It means that out of the 168 puppies born, 128 out of the 168 born that year has had their hips and elbows x-rayed.

jaktavlade_rontgade

This is really interesting. The Field Golden retrievers have a remarkably higher amount of dogs getting x-rayed than the breed average. In fact, they are reaching the goal of the Golden Club in all years, with exception for 2012, when they missed the goal with 1%. The average of Field Goldens getting x-rayed is 71%, which should then be compared with the total breed average of 55%.

Why is it like this? One can only speculate, but one reason could be that the breeders and buyers of Field Goldens are often very active dog people, which means the status of the joints are important for the job the dogs are supposed to do. In contrary, the buyers of the so called Show Goldens are more often families with no reason to x-ray unless the dog shows any symptoms of HD or the breeder is insisting on getting the dogs x-rayed.

I am aware that comparing Show and Field Goldens is very sensitive to some people, and I want to underline that I, in absolutely no way, am saying that one type of dog, breeder or buyer is better than the other in any way! I am merely speculating about why the difference in the amount of dogs getting their x-rays done differs that much! If you have other thoughts about this, please feel free to speculate in the comment section!

The consequence of this is that the HD statistics for Field Goldens is much more reliable (as more dogs have known status) and also that they have a much more accurate breeding index. I think that the Golden Club needs to think about a strategy to get more dogs x-rayed and not focus so much on how the images are interpreted and whether retaking the x-ray will improve the result or not (these are some of the points they raise). But that’s my personal opinion.

GOAL 2: Number of dogs with Hip Dysplasia grade D and E to be less than 8 percent

This is how the x-ray results are looking for the entire breed:

HD_resultat_rasen

And this is how it looks for Field Goldens:

HD_resultat_jaktavlade

When comparing the overall breed result with Field Goldens, one can see that Field Goldens have a slightly higher percentage of the dogs who are HD free. In the period of 2010-2015, 79,91% of the Field Goldens were HD free, whereas for the entire breed the figure is 75,05%. Looking into the dogs diagnosed with HD, the difference in amount of dogs with grade C is only about 1%. But if we look at the dogs diagnosed with HD grade D and E, the amount differs. While the breed in total has an average of 7,98% of the dogs diagnosed with HD grade D and E, the Field Goldens only has an average of 4,13%.

The reason for this could be the population size – it is a small portion of Field Goldens in comparison to the overall breed. It could be that family dogs are more often only x-rayed when they show symptoms of hip dysplasia – which means many positive results are missed out. And of course one reason could be less focus on hip status in the breeders’ breeding strategies.

The above figures means that the Golden Club reached the goal to have the number of dogs with Hip Dysplasia grade D and E to be less than 8%. No matter the reason, I believe that 8% is way too much. In actual numbers, it means that in 2010-2015, 493 Golden retrievers was diagnosed with severe hip dysplasia. Think about it. Think about what that means to each individual dog and dog owner.

It is good that the goal was reached, but I really hope that the new strategy is setting a tougher targets this time. Hopefully, we are all working to limit the amount of dogs with hip dysplasia and that means challenging ourselves to be better, to improve and put in that extra effort.

If you found this interesting, let me know. And please also just tell me if there is any aspect you would like me to dig extra deep into.

In my next post, I will dig into the statistics of elbow dysplasia and in another post I’ll try to explain what hip and elbow dysplasia is in a way that is understandable to anyone :)!

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