Survival of lambs from maiden ewes may not be improved by pre-lambing exposure to mature lambing ewes

The survival of lambs born to ewes at their first (maiden) lambing is generally lower than for those born to ewes which have previously lambed, and poor maternal behaviour is a contributing factor. This study examined whether pre-lambing exposure of maiden ewes to multiparous lambing ewes would improve the survival of lambs born to maiden ewes. Pregnant maiden (n = 333, 2 years of age) Merino ewes were allocated to three replicates of two treatments: exposed – maidens were grazed with multiparous Merino ewes (n = 111, 5 or 7 years of age), which were due to lamb during the 2 weeks before the start of maiden lambing, with mature ewes comprising 50% of the mob size; and non-exposed – maiden ewes grazed in paddocks without mature ewes. The total number of ewes per paddock (74), number of ewes per hectare (14.0) and paddock size were the same in both treatments. The number of lambs born per ewe was similar between treatments, indicating a similar proportion of multiple births. The proportion survival of lambs from maiden ewes exposed to adults (0.53) tended to be lower (P = 0.091) than the survival of lambs born to maiden ewes grazing alone (0.61). The number of lambs marked per ewe lambing was similar (P = 0.284) in exposed (0.71) compared with non-exposed (0.78) maidens. The survival of lambs from maiden ewes was not improved by lambing in the same paddock with adults, even where the adults had largely completed lambing before the maidens commenced.