Genetic parameters of two methods of scoring cow fighting ability

In this study, two different methods of scoring were implemented and compared in reason to assign a correct phenotypic value to cow fighting ability, and the variance components of the trait were estimated. Moreover, it was investigated the correlation of the estimated breeding values (EBVs) for fighting with the EBVs for the linear type traits muscularity. A scoring method mainly based on position (PS) and a method considering opponents’ performances (CPS) were compared and used in genetic analyses. A correlation of 0.75 between EBVs associated to PS and CPS was obtained, and ANOVAs considering alternatively PS and CPS indicated almost the same magnitude of the different sources of variation included (R2=0.50 and 0.52 for PS and CPS, respectively). Heritability estimates with the REML method were 0.099 (S.E.=0.005) for PS and 0.034 (S.E.=0.007) for CPS. Pearson and Spearman correlations between both indexes and ranks were no significant. Finally, an evaluation of the fitness of the two models revealed that PS is the better system for scoring, although CPS was designed to account also for the opponents.