Lambs Weaned Early onto a Herb-Clover Mix Have the Potential to Grow at a Similar Rate to Unweaned Lambs on a Grass-Predominant Pasture

SIMPLE SUMMARY: Early weaning of lambs may be a useful management tool when either herbage quality or quantity limits lamb growth. Herb-clover mixes containing chicory, plantain, red clover, and white clover have been shown to improve the growth of suckling lambs and those weaned at a traditional age compared to grass-predominant pastures in New Zealand. In this study, lambs were weaned at a minimum live weight of 14 kg and their liveweight gains at a conventional weaning age (~99 days of age) were compared with lambs unweaned on a grass-predominant pasture. We found that lambs weaned early onto a herb-clover mix have the potential to achieve live weights similar to lambs unweaned on grass-predominant pasture. ABSTRACT: Liveweight gain of lambs weaned early at a minimum live weight of 14 kg, at ~50 days of age, onto a herb-clover mix was compared with lambs that remained unweaned on a grass-predominant pasture or a herb-clover mix until conventional weaning (at ~99 days of age). Over two years, twin sets of lambs that had a minimum live weight of 14 kg were randomly allocated to one of three treatments: (1) Early weaning of lambs onto a herb-clover mix (Herb(EW)); (2) ewes and lambs grazing a herb-clover mix until conventional weaning (Herb(CW)); and (3) ewes and lambs grazing a grass-predominant pasture until conventional weaning (Grass(CW)). Herb(EW) lambs had slower (p < 0.05) growth rates than Grass(CW) lambs between early weaning and conventional weaning in 2016 and were 800 g lighter (p < 0.05) at conventional weaning. In 2017, however, both Herb(EW) and Grass(CW) had similar (p > 0.05) growth rates and did not differ (p > 0.05) in live weight at conventional weaning. Herb(CW) lambs had a greater (p < 0.05) growth rates than both Herb(EW) and Grass(CW) lambs in both years. Lambs weaned early onto a herb-clover mix have the potential to achieve live weights similar to lambs unweaned on grass-predominant pasture. Further research, however, is required to understand conditions under which early-weaned lambs can achieve similar live weights.