Gordon Setter hip analysis

The Gordoner, 2008

There tends to be a constant turnover of people, be they exhibitors, breeders or whatever, who are involved in any given breed at any one period of time. This applies to all breeds and Gordon setters are no exception. As this is the case, and as it seems to have been some considerable time since there have been any articles or features in any breed Newsletters or Year Books concerning hip scores and hip dysplasia (HD), I feel that there may be many who are now involved who will benefit from an article giving a very general overview of these.

History

First reports of canine HD appeared in American Journals in 1935 but it received little publicity until the 1950’s. Over the following ten years serious research began and schemes to combat HD were set up initially in Scandinavia. A scheme was set up in Britain under the auspices of the GSD League in 1961 but this was abandoned in 1965 when the BVA scheme began.

To start with the BVA/KC scheme simply categorised hips as Certificate, Letter or Fail which corresponded to Normal, near Normal or Failure. Total submissions to this scheme from all breeds rarely exceeded 400 per annum. During 1978, Dr Malcolm Willis, acting on behalf of the GSD Improvement Foundation, approached the BVA to consider another scheme. Prof Lawson, who was the Chief Scrutineer of the BVA panel, put forward the idea of the scoring scheme and by late 1983 the old BVA/KC scheme was abandoned for all breeds in favour of the scoring scheme as we know it today.

Gordon setter breeders became more and more concerned about hip problems and they approached Dr Willis for help and guidance at the start of 1984. Dr Willis was Senior Lecturer in Animal Breeding & Genetics at Newcastle-upon-Tyne University, a renowned author on Genetics and GSD’s; he also maintained comprehensive data on hip scores in all breeds. For many years he supplied Gordon Breed clubs and individual breeders with help, information and detailed annual reports which were included in Year Books or Newsletters.

Report content

As far as I am aware, the last time any Gordon breed club published a full report from Dr Willis was in 1992, and as I write this I can see that his report covered up to 23 June ’92; as we are now at June 2008, that is 16 years ago! Dr Willis has not been in good health recently but as his reports were comprehensive and provided information which was specific to Gordons, I am surprised that nobody seems to have continued maintaining these types of statistics and made them available.

The 1992 report gives overall figures for scoring in Gordon setters; at that time a total of 880 Gordons had been scored, which included 41 Australian scores. The scores ranged from 0 – 104 with a mean score of 25.70 for British Gordons, which reduced to 25.05 when the Australian data was included.

I felt that it would be more prudent – and better received by Gordon setter breeders – if an ‘official’ up to date analysis could be obtained. With this in mind I approached Prof Jeff Sampson, KC Genetics Consultant, and the following is the report he kindly compiled. I forwarded it to the British Gordon Setter Club and it reproduced it in its Newsletter.

Analysis of Hip Scoring results for the Gordon Setter

by Dr Jeff Sampson, Kennel Club Genetics Consultant. July 2008

I have been asked to provide an update of hip scoring in the Gordon Setter, analyses that have been provided by Dr Malcolm Willis in the past. Dr Willis was the consultant to the BVA/KC Hip Scoring Scheme and as such probably had access to more data than is available to me. The following analyses have been produced from data that has been deposited on the KC Registration Database since 1992, to which I have access, and will closely approximate to the data available to Dr Willis.

Table 1 reflects the trends in hip scoring since 1992 and I have chosen to use the concept of a 5-year rolling mean (median) to demonstrate these trends. So, the 1996 mean (median) reflects all dogs scored in the previous 5 years, i.e. from 01/01/1992 to 31/12/1996. Then, to compute the 1997 mean (median) the start and finish year moves on by one, so the 1997 mean (median) reflects those dogs scored between 01/01/1993 and 31/12/1997, the 1998 mean (median) is computed from dogs scored between 01/01/1994 and 31/12/1998, and so on ending with the 2007 mean (median) representing those dogs scored between 01/01/2003 and 31/12/2007. Remember, the mean is the arithmetic average of all dogs scored, i.e. the sum of all of the scores in the period divided by the number of dogs scored in the period. The median is the middle value in a distribution, above and below which lie an equal number of values.

Table 1

5-year Rolling Trends in Hip Scoring between 1992 and 2007

Note: * to the nearest whole number

This table paints a very encouraging picture for the breed, exemplified by the year on year fall in the 5-year rolling mean and median values. Often criticism of the scheme, and the progress seen by these analyses, is that the downward trends are simply the result of an increasing trend for breeders/owners not to submit the radiographs of high scoring dogs on the advice of their vet. I am sure that this does happen, although under the scheme rules it shouldn’t, but these results do not support this as the reason for the improvement seen. Yes, the results do show that during this period the percentage of dogs scoring greater than 30 has reduced by 50%, but this is accompanied by a 50% increase in the percentage of dogs with scores less than 10. I think that this shows that these data are demonstrating a genuine year on year improvement in the average hip scores in this breed.

Progeny testing using dogs scored since 01/01/1992, for sires that have had 10 or more progeny scored during this period.

In the past Dr Willis has produced average progeny scores for individual sires. The last time that he did this for the Gordon Setter was in 1992, so I have taken this analysis from 1992 until the present time (See separate table). Average progeny scores can give a lot of information about a particular sire and the kind of progeny that the sire is likely to produce. Obviously, this will depend on the number of scored progeny for each sire; to quote Dr Willis, “Progeny averages on 5 progeny are about as reliable as the dog’s own hip score. This, in turn, would depend on heritability. Averages from 20 progeny are more reliable than the dog’s own hip score to the point that the dog’s own hip becomes almost irrelevant”

Table 2

Mean Progeny Scores for Sires that have more than 10 scored progeny, scored between 01/01/1992 and June 2008

Note: Although some sires are recorded as ‘NS’ they may very well have been scored but prior to the KC recording &/or publishing these.

So, in this table I have listed the average progeny scores for all sires that have had 10 or more progeny scored during the period. I have listed the dogs, in order of average progeny scores. I have listed the number of scored progeny, together with total registered progeny for sire, and the number of dams that have produced these scored progeny with the sire. I have also listed the range of progeny hip scores, together with the percentage of progeny that fall within various hip score ranges. Finally, obviously the hip score of progeny not only depends on the sire score, but also the dam score, so I have also indicated the range of scores in the dams mated to the sire. ‘NS’ means that the dams have not been hip scored. The sire’s own hip score is given in parenthesis; ‘NS’ showing that the sire was not scored.

It is worth repeating the advice that Dr Willis has given in the past:

“The way to reduce hips score means is to initially breed from the better (lower) scored animals and, as progeny data become available, breed from those animals which are producing lower mean scores and better distributions of scores”.

“In the tables below the sires are listed in ascending order of mean progeny score based on an arithmetic mean. “In looking at these rankings one must not think that a dog with a mean of say 14.1 is better than a dog with a mean of say 15.5, since both are in a similar area. However, dogs that have wide differences are likely to be truly different. One must, of course, take account of the number of progeny available. The more progeny scored (for a given sire), the more reliable the information”.

“In using these tables, remember that lower progeny scores are better and higher progeny numbers from large number of dams are also better. In looking at the ranges of progeny try to use sires with high percentages of progeny in the lower score ranges (0-5, 6-10 and 11-20) and low percentages in the higher score ranges (above a score of 30)”

Bonnie Scougall writes: Although Prof Sampson has marked a number of the sires/dams as ‘not scored (NS)’, readers should note that in the majority of cases, these Gordons were in fact scored. As it was prior to the KC publishing all scores, perhaps it would be advisable to read it as ‘not recorded’.