• Rebecca Elder

Breed improvement

There is a lot of lip service given to breeding to improve the breed. No doubt everyone has their own opinion on what, exactly, needs improvement and objective, measurable criteria to gauge that success are lacking in most categories.

One category where it is possible to measure improvement is in health testing. Over time, the incidence of Progressive Retinal Atrophy (PRA) in the breed has declined significantly starting with the release of the DNA test in 2002. Because of the mandatory reporting option chosen by the ACDCA with Optigen, the OFA results provided a complete and true picture of the in incidence of PRA in the breed over time (at least up until the proliferation of inexpensive gene testing companies that did not agree to mandatory reporting of results a few years ago but that is another subject entirely).

At the start of DNA testing in 2002, the breed average was close to 25% clear and 25% affected with the rest being carriers, as would be expected with a simple recessive trait. Since that time, the clears have trended up until currently they are well over 60% of all new tests while affecteds have declined to an almost negligible amount. The importance the ACD community places on PRA status can easily be seen both in this data and in the ever increasing number of breeders who test for PRA and other DNA testable eye diseases and nothing else.

Meanwhile, another issue in the breed that has decades of testing data to look at is getting appreciably worse since the PRA test was released: Hips. The Orthopedic Foundation of America (OFA) tracks health testing by breed on all submitted reports whether the owner makes the results publicly accessible or not. All submitted test results go into their statistics. Because moderate to severe hips scores are obvious, they are frequently not submitted which artificially raises the average hip score by deleting the extremes on the bad side so the data is not perfect but it still shows us useful and significant trends in cattle dogs.

Considering the breed as a whole, greater than 90% of ACD radiograph submissions fall from Good to Mild. We must discount the numbers of Moderate and Severe due to a bias towards not submitting those radiographs. I have also discounted the Excellent numbers as the breed averages 6 Excellents a year out of 200 submissions and the goal is to focus on breed trends in categories with more statistically significant numbers.

Using 2002 as the dividing line (the year the PRA gene test was released), there has been an obvious decline in hip scores which I would postulate is secondary to the immediate shift of focus to eyes at the expense of the whole dog.

Because a varying number of dogs are submitted each year, the data must be evaluated by trends and percents rather than number of dogs in each category. The OFA graph shows the trend but in the interest of sharing the information clearly, I have arbitrarily chosen a percent for the categories of Good, Fair and Mild and then compared how often we hit that percent of dogs receiving that rating up to and including 2002 and then from 2003 on, i.e., the number of times we have hit X% of dogs receiving that hip score up to 2002 and after 2002. If hips are improving, the percentage of good hips should be increasing while fair and mild hips should be decreasing. I have excluded borderline, moderate and severe evaluations as moderate and severe are often not submitted and borderline are recommended to be resubmitted to be rescored for an actual rating so that data is flawed rather than useful.

What we see instead of improvement is a consistent trend in declining hip scores since 2002. For the rating of Good, the most common rating, the breed ranges from 50-60% in the Good category in general. Taking 55% as the over/under point, up to and including 2002, the ACD hit that goal 15 out of 22 years or 68% of the time. After 2002, the breed hit that goal 6 out of 16 times or 37%, meaning we made that goal almost half the amount of time as we did previously.

For Fair hips, taking 25% as the over/under point, prior to 2003, 13 out of 22 years, or 59% of the time, a quarter of the breed received a rating of fair hips. After 2002, 1 out of 16 years saw that percentage. On the face of it, this is good news as potentially those genetics have been improved to good - except they clearly haven't because we are producing fewer goods than before.

When looking at the next category, things get even worse. For hips scoring as mildly dysplastic, taking 10% of the breed as the arbitrary over/under point, prior to 2003, there were 13 out of 22 years, or 59% of the time, where the breed received mildly dysplastic ratings on more than 10% of the submitted dogs. After 2002, that jumps to 14 out of 16 years or 87%, meaning more than 10% of the submitted radiographs are failing almost every year - and that number is increasing even with clearly failing hips rarely being submitted for evaluation.

The OFA also releases information on what percent of the submissions are marked for public database submission and those numbers are, to my mind, appalling. In any given year. typically fewer than 30% of the people submitting radiographs give the OFA permission to release all scores good or bad. This means that most failing scores are hidden which is a tremendous handicap to breeders trying to do due diligence and research hip pedigrees to breed for improvement. Not only are we actively selecting away from good hips, we are interfering with the ability to select for good hips if we wanted to.

The public database is skewed towards giving a better picture of hips in the breed than is accurate but the breed statistics do not lie.

Hips are getting worse.

We need to do better as a breed. We cannot pretend to be breeding better dogs when we are failing to breed for the whole dog and deliberately sabotaging both the present and the future by failing to test or by hiding results. To improve a breed, one must first know where one stands and what needs improvement, then go forth and conscientiously and honestly work for improvement - this means in more ways than just clear for PRA and for reasons other than just how quickly a puppy can mature and win in the show ring. It doesn't mean flush a great dog for one flaw but it does mean accept that there is a flaw and address it, honestly.

https://www.ofa.org/diseases/breed-statistics

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