Genetic parameters estimates for ewes’ behavioural reactivity towards their litter after lambing
Résumé
In livestock, improving maternal reactivity towards the litter is an important issue in
breeding strategies to promote production and animal welfare. As of yet, no studies
have investigated the within-breed genetic variation of maternal reactivity in sheep.
The objective of this study was to estimate the genetic parameters of maternal reac-
tivity traits. A total of 1,095 primiparous and 1,441 multiparous Romane ewes were
phenotyped 24hr postlambing using a behavioural test (arena test, AT) over a 10-
year experimental period. The test consisted of three successive phases evaluating the
ewe's attraction to her litter, reactivity to separation from her litter, and reactivity to
a conflict between attraction to her litter and avoidance of a motionless human. The
ewes were reared exclusively on rangelands (South of France) and lambed outdoors
in the spring. High-pitched bleating and low-pitched bleating in the AT were mostly
highly heritable (0.39‒0.46). Heritabilities were moderate for proximity to the litter
in the presence of a human (0.27) and low for locomotion and vigilance in the AT
(0.09‒0.15). The measurements of a given behaviour in the three phases of the AT
were highly genetically correlated. Few genetic correlations were found between the
different behavioural traits in the AT, the highest correlations being between high-
pitched bleating and low-pitched bleating (−0.43 to −0.77). In conclusion, our find-
ings demonstrate moderate-to-high heritability for maternal reactivity traits. These
traits could be included in genetic selection schemes to enhance maternal attachment
provided there is no unfavourable link with other production traits.