Lifetime productivity of single- and twin-born Corriedale sheep and their dams

Abstract

Differences in the productivity of twin- and single-bearing, spring-lambing Corriedale ewes and their progeny were studied over 8 years at the Experimental Station, Faculty of Agriculture, Paysandu, Uruguay. Lambing ewes, grazing improved pastures during late pregnancy and early lactation, produced 9.7% less wool than dry ewes, gestation and lactation accounting for 4.5 and 5.2% of this difference, respectively. No difference in wool production was found between ewes rearing 1 or 2 lambs. Twin-born sheep produced 1.8% less wool than singles, but the difference decreased with age. Twin-born ewes had a 7.5% higher lambing rate than single-born ewes, but the mortality rate among their lambs was higher (37.1 v. 20.4%). The liveweight of single-born sheep was higher than that of twins by 20.4%, 16.0% and 11.4% at marking, weaning and 11 1 days of age, respectively. We suggest that the difference in productivity between twin- and single-bearing ewes, and their lambs, can be minimised by adequate nutrition in late pregnancy and early lactation.