Genetic associations between temperament and performance traits in Nellore beef cattle

SummaryThe aim of this study was to estimate genetic associations between tem-perament and performance traits. Temperament was evaluated in yearlingmale and female Nellore cattle, using four traits: temperament score (TS),for assessing animals’ reactions in a corral pen (n = 25 691); movementscore (MOV), for animals’ movements recorded inside the crush; crushscore (CS), for animal’s general reactivity inside the crush; and flightspeed (FS), for the speed (in m/s) at which the animals exited the crush(n = 11 697, for the last three methods); for all the temperament traits,lower scores indicate animals with calmer temperament. Performancetraits were visual scores for conformation (C), finishing precocity (P) andmuscling (M) evaluated at yearlings, and average daily gain (ADG) wasestimated from weaning to yearling. Bayesian inference using Gibbs sam-pling was applied to estimate (co)variance components and genetic andphenotypic parameters. Heritability estimates for the temperament traitsranged from 0.07 (CS) to 0.28 (FS). Genetic correlations of the tempera-ment traits with ADG and C, P and M were negative and ranged from 0.02 to 0.31. Phenotypic correlations were negative and consistentlylower than the genetic, ranging from 0.08 to 0.02. It was concludedthat the temperament traits assessed had favourable genetic correlationestimates with the performance traits studied. However, indirectresponses in temperament when selecting for higher ADG and visual scor-ing system of C, P and M, will be low.IntroductionTemperament can be defined as individual differ-ences in behavioural responses which are persistentover time and across situations. Cattle temperamenttraits are usually assessed from behaviouralresponses of the animals under human influenceduring handling procedures (Fordyce et al. 1985)and related to cattle welfare, stockperson safety andefficiency of handling. Furthermore, there are severalreports where these traits are related to importantaspects of cattle production, for example reproductiveefficiency (Cooke et al. 2012), growth rate and meatquality (Petherick et al. 2002; Behrends et al. 2009).Despite the large number of studies addressing thistopic, there is no consensus about the extent towhich temperament traits may affect productiveperformance, as some authors reported strong rela-tionship (Petherick et al. 2002; Behrends et al.2009), whereas others reported only a weak associa-tion (Burrow & Corbet 2000; Burrow 2001).These varying results could partially be associatedwith different rearing conditions, which could affectthe expression of temperament traits and, conse-quently, the degree of their association with perfor-mance (Fordyce et al. 1985; Burrow & Corbet2000). To overcome this difficulty, it would berequired assessing the temperament of cattle from a