Possibility of selecting racehorses on jumping ability based on their steeplechase race results in France, the United Kingdom and Ireland.

The aim of this study was to detect Thoroughbred mare families and sire lines, in France, in the United Kingdom and Ireland, whose offspring may be successful in steeplechase races and can be recommended therefore for sport horse breeding. Race results were collected from all steeplechase races in these countries between 1998 and 2003, which contained the results of 17,355 horses from 12,861 dams and 2452 sires. In France, non-Thoroughbred horses were also included in the analysis because they race and mate together with Thoroughbreds. Performance was measured with two criteria: earnings and ranks after mathematical transformation. The effects of year, sex, age and race were considered as fixed, animal, permanent environment and maternal environment as random. Precorrection for the effect of race was done to avoid computational difficulties. Maternal environmental components for ranks were 0.02 in France and zero in the United Kingdom and Ireland. Estimated heritabilities for the ranking criteria were 0.18 (repeatability 0.33) in France and 0.06 (repeatability 0.19) in the United Kingdom and Ireland. The high genetic correlation between the two criteria of measurement (0.94 and 0.97 respectively) gives the opportunity to choose the most suitable criteria for breeding value estimation. The ranking value, after statistical normalization has a great advantage for comparison between the countries.