Duration of phase II of labour negatively affects maternal behaviour and lamb viability in wool-type primiparous ewes under extensive rearing

Abstract This study determined to what extent the duration of labour phase II under extensive rearing would affect lamb viability and maternal behaviour in primiparous (P) single-bearing Corriedale ewes (n = 63). Multiparous (M) ewes (n = 116) were used as control category, reared under the same conditions. Duration of labour was divided in 4 time-groups, G1: ≤ 30 min; G2: 31- 60 min; G3: 61 - 90 min and G4: ≥ 90 min for each ewe category. Body condition score (BCS, scale 0-5), duration of labour, delivery assistance, maternal behaviour score (MBS, 1-5) and presence of grooming after parturition were recorded and length of gestation calculated. Lambs were Apgar tested (score 1-10) at birth; time elapsed to stand and successful suckling during the first two hours of birth was recorded as well as birthweight (BW) and mortality during their first 72 h. Prepartum BCS was similar between categories, while P ewes showed shorter gestation (147.2 ± 0.3 vs. 148.0 ± 0.2 days, P = 0.0474), longer expulsion phase (50.5 ± 4.2 vs. 32.2 ± 2.6 min, P