Genetic parameters for jumping performance in Brazilian Sport Horses

Abstract

This study aimed to estimate genetic parameters for jumping measures in the Brazilian Sport Horses breed, looking to see which jump characteristics can be evaluated early and that present favorable genetic correlations (ϒg) with measures of later sports performance. Data were available for the results of jumping competitions on the Brazilian Sport Horses. Two traits were calculated: Classification (CLASS) of the animal (taking into consideration obstacle height, number of competitors, type of competition (regional, national, international) and final score (SCOREF) taking into consideration the weight of the competition, height of the obstacles and score for the placement and type of event. Heritabilities were low for the full database (0.00 and 0.07 for CLASS and SCOREF, respectively), but higher when only young horses were considered (0.09 and 0.67, respectively). Genetic correlations between these traits and subjective functional traits (using a scale of 0 to 10) measured at stallion approval for reproduction showed that Power was favorable for indirect selection for both traits (-0.85 for CLASS and 1.00 for SCOREF). Jump also showed a favorable correlation for SCOREF (0.53) but unfavorable for CLASS (1.00). Considering the importance of Temperament and the absence of unfavorable genetic correlations between it and competition results it was concluded that this trait can be maintained among the selection objectives of Brazilian Sport Horses. Suggestions are made for further genetic studies with this breed, and possible modifications in the evaluation regulations to improve data quality. Keywords: competition; final score; genetic correlations; heritability; temperament