Temperament and its heritability in Corriedale and Merino lambs

Abstract

Temperament can be defined as the fearfulness and reactivity of an animal in response to humans and strange, novel or threatening environments. The productive performance of an animal is affected by its temperament, and selection of calm animals might improve their adaptation to the farming environment and handling, as well as improve productivity. The temperament was measured in lambs of two breeds of sheep in Uruguay. The effects of dam's age, type of birth, age of the lamb and contemporary group (CG; lambs belonging to the same year, flock, sex and rearing group) on the temperament of the lambs and the heritability of temperament were estimated with a Bayesian analysis using Gibbs sampling. Overall, 4962 Corriedale lambs and 2952 Merino lambs from 13 farms were tested. Temperament was measured using the isolation box test, isolating a lamb inside the box for 30 s, and recording the vibrations produced by its movements. The average temperament score (± s.e.m.) of the Corriedale lambs was 24.7 (±0.23) and that of the Merino was 36.8 (±0.45). Temperament was not associated with dam's age, type of birth or lamb's age. There were no relevant differences in the agitation score between lambs born in 2010 and 2011. The mean of the distribution of possible values of heritability (± s.d.) was 0.18 (±0.05) for the Corriedale and 0.31 (±0.06) for the Merino. The likelihood of heritability values to be greater than 0.15 exceeded 70% in the Corriedale and 90% in the Merino. The temperament of Merino and Corriedale sheep in Uruguay is moderately heritable. It is not related to dam's age, type of birth or age of the lambs; however, it is affected by some aspect of the CG.Keywords: sheep temperament, emotional reactivity, Gibb's sampling ImplicationsObjective selection for calm sheep may improve animal welfare and economic performance of sheep flocks. We assessed the temperament of Uruguayan lambs (reactivity to social isolation) with a simple test -the isolation box test (IBT). This trait had a heritability of 0.18 in Corriedale lambs and 0.31 in Merino lambs; therefore, temperament (assessed by IBT) can be considered as a potential selection tool for sheep. IntroductionSince domestication, natural and artificial selection have led to the adaptation of animals to different types of production environments. However, farmers still have to deal with low lambing rate and high lamb mortality (Simm et al., 1996). Artificial selection for behavioural traits in species of economic value can improve adaptation of the animals to production environments. The expression of undesirable behavioural traits in livestock has the potential to significantly compromise farm viability, animal welfare, human safety and labour efficiency (Turner et al., 2011). Fear and emotional reactivity (temperament) are behavioural elements in cattle and sheep, which are heritable and can have genetic and phenotypic associations with reproductive performance and lamb survival (Murphy, 1999;Reverter et al., 2003;Kadel et al., 2006;Turner et al., 2011). In sheep...

Association between temperament related traits and single nucleotide polymorphisms in the serotonin and oxytocin systems in Merino sheep

“…The ock is kept at the UWA Farm Ridge eld, Pingelly, Western Australia. The temperament of the sheep in the ock was assessed within two weeks after weaning at around 16 weeks of age using two behavioural tests that are described in detail below under phenotyping of sheep temperament [6]. An overall selection score was calculated for each animal by combining the results of two tests [9].…”

“…Isolation box test: Within two minutes after the completion of the arena test, each sheep was introduced into, and locked in, an enclosed wooden box (H: 1.5 m × L: 1.5 m × W: 0.75 m) and left for one min while deprived of visual contact with conspeci cs [6]. The level of vibration of the box that was produced by the movement of sheep and the high pitch bleats were recorded by an apparatus (agitation meter) that was xed to the outside of the box [8].…”

“…Temperament is of more than academic interest because temperament can influence immunity, and production traits such as ovulation rate, growth performance, and meat quality 4‐6 . In sheep, the phenotype and the genetic heritability of temperament traits have been assessed using behavioral tests like an arena test and an isolation box test 7‐9 . Similarly, the temperament of bovines has been assessed for decades using behavioral tests such as the open field arena test, a flight speed test, an exit velocity test, and a crush score test 4,10,11 .…”

“…The temperament of each of the 260 sheep in Part 2 was assessed using an open-eld arena test and an isolation box test[6,9,11].…”

Estimation of genetic parameters for temperament in Jeju crossbred horses

“…They reported moderate level of heritability for the temperamental trait [ 6 ]. In sheep, Zambra et al [ 7 ] demonstrated that the temperament of Uruguayan Merino and Corriedale sheep is moderately heritable. In cases of horses, there is a study estimated genetic parameters for the behavioral response of Thoroughbred horses at medical checkups for horseracing [ 8 ].…”