How gene ratings can help you choose a jumping sire
Genetic evaluations can focus the mind when it comes to selecting the right jumper, writes Norman Storey, equine specialist, Teagasc Kildalton
The dairy industry has been using genetic evaluations to predict the breeding value of bulls for many years. They have been used to increase milk yield, butterfat and protein levels very successfully.
The KWPN in Holland are using genetic evaluations for stallions very successfully. They have figures for improvement in a number of characteristics such as jumping, dressage, conformation, movement and a reduction in OC.
The Irish Horse Board recently announced the results of the 2007 'Genetic Evaluations for Approved Stallion'.
The report contains Estimated Breeding Values (EBV) for show jumping, athleticism, temperament, movement and conformation.
What are EBVs?
Estimated Breeding Values are predictions of the genetic advantage that a stallion or mare will pass on to its offspring for a particular trait.
In simple terms, as we all know, a stallion like Cruising or Clover Hill is more likely to breed jumpers than other stallions. EBVs estimate how much that improvement can be expected in the offspring.
How are EBVs calculated?
EBVs are calculated from a horse's own performance in competition and from the performance of all its relatives, including parents and progeny. At the end of each jumping competition run by the SJAI, tickets are completed for each horse that competes. Completed tickets are submitted to the SJAI and the information contained is used by the Horse Board to calculate EBVs.
Every result is important -- even the bad ones. If we are to get accurate predictions of the breeding value of a stallion we must include the bad results as well as the winning ones. If we only included the good ones, we could get a very false picture of performance. As we know, many stallions breed bad performers as well as good ones, so their results must be included.
EBVs for athleticism, temperament, movement and conformation are based on the results of the IHB stallion and mare inspections. Again the good and the bad results are included.
Understanding the results
EBVs are expressed as an index with an average value of 100. An individual stallion's EBV measures the difference between its genetic ability and the average of the population.
The higher the EBV figure, the better. For example a horse with an EBV of 140 for jumping will have a better chance of breeding jumpers than one with a value of 120.
On the other hand, stallions with values below 100 are unlikely to improve that character in its offspring.
The more information that is included in the EBV the better. The result will be more accurate or reliable.
For example, if only one competition result is included, the EBV would not mean very much.
But if 100 or more are included, the EBV can be a very reliable guide to a stallion's breeding value.
So the accuracy can range from 0 to 1. More information results in a higher accuracy. EBVs with an accuracy of 0.7 or greater have a good level of reliability.
Using the results
EBVs are of course not the complete answer to breeding. They must be regarded as another tool for breeders to use when selecting stallions. As more results are included they will become more reliable.
At present, only national jumping results are included, so the majority of the results are from the lower grades of competition. International competition results are not. Dressage and eventing results are not included.
Thoroughbred stallions do not usually score very high, as they have little or no jumping performance.
Despite these limitations, breeders should start using EBVs as part of their selection of stallions for breeding programmes.
The highest-ranking stallions
Show jumping EBVs predict the jumping ability of a stallion's offspring. For stallions with EBVs greater than 120, 70pc of their offspring who compete in show jumping competitions will reach the level of 1m30 competitions or above. This rate falls to only 15pc where the EBV is less than 100.
Foals by stallions with EBVs for jumping ability above 120 achieve, on average, €1,100 more at auction than foals by stallions with EBVs below 100.
Foals out of high EBV mares achieve on average €2,200 more than foals out of low EBV mares. The breeding values are displayed in an easily understood bar chart.
The highest-ranking stallion for 2007 is Hermes de Reve with a jumping EBV of 147. However the accuracy figure is below 0.7 at 0.69 and as it is still a young horse no progeny was included.
One can easily see that he is likely to improve all characteristics in his progeny except forelimb conformation, so mares he is covering must have a good front leg. The other top 10 stallions are Flex a Bill, Portorico, Clover Flush, Leeroy, Captain Clover, Warrenstown You 2, Sir Rivie, Down Jones Courcel and Cruising.
This sort of information certainly focuses the mind when it comes to selection time. What are you trying to breed?
- Norman Storey
