Genetic determinism of maternal behaviour in sheep and relationship with lamb mortality

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Hazard, Dominique | Kempeneers, Amandine | Foulquie, Didier | Carriere, Fabien | Delval, Eric | Boissy, Alain

Edité par CCSD ; Wageningen Academic Publishers -

Increasing behavioural autonomy of animals ensures their adaptation to various environments and contributesto the sustainability of livestock production. More particularly, maternal behaviour is vital for the offspringsurvival. Breed differences in maternal behaviour are well known but genetic variation within breed has beenpoorly investigated. The aim of the study was to estimate in sheep genetic parameters for maternal reactivityand search QTL associated with the related behavioural traits. Ewes (n=851) reared outside were individuallyphenotyped just after lambing in two behavioural tests based on the reactivity to separation from their lambsand/or to a human. Ewes were tested for one or two lambing. In the first test performed outdoor 2 hours afterlambing, the ewe’s reactivity was assessed by measuring flight distance from lambs, time to restore contactwith lambs and facility to follow transport of lambs. In the second test performed indoor 24 h after lambing,the ewe’s reactivity was assessed by measuring vocalizations, locomotion and proximity to lambs with orwithout human presence. Lamb mortality was recorded until weaning. Heritability estimates were moderate(h2=0.11 to 0.23±0.05) for flight distance from lambs, time to restore contact with lambs and facility to followthe transport of lambs. Genetic correlations between these traits ranged from 0.78 (±0.21) to 0.95 (±0.06). Forthe second test, heritability estimates ranged from 0.11 (±0.05) for proximity to 0.50 (±0.05) for vocalizations.Genetic correlations ranged from 0.13 (±0.06) to 0.44 (±0.07). Lamb mortality was significantly lower in ewesshowing a higher maternal reactivity. A genome wide association study of maternal reactivity is currentlycarried on in ewes genotyped using the Illumina ovineSNP50 beadchip. The moderate to high heritabilities andpotential SNPs polymorphisms for the behavioural traits of ewes may offer opportunities in genetic selectionfor improving maternal behaviour and reducing lamb mortality.

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