Managing the weaning transition of Merino lambs by promoting positive growth rates and increasing survival – is yard weaning a viable option?

Abstract

The effectiveness of yard weaning to manage the weaning transition period for Merino sheep was investigated on three commercial properties in the New South Wales Central Tablelands. Three experiments were conducted, Experiment 1 investigated the duration of yard weaning, Experiment 2 compared two alternative rations provided to yard-weaned animals, while Experiment 3 compared yard weaning with paddock weaning. The ‘Control’ for each of the three experiments was each producers’ normal paddock-weaning strategy with comparisons based on post-weaning growth rates and weaner survival. Liveweights were recorded at weaning and at 15, 50 and 180 days post-weaning. Growth rates were calculated from liveweight measurements. Survival was determined by the continuing presence of an individual animal at subsequent measurements. Compared with the paddock-weaned Control group, variable responses in liveweight, growth rates and weaner survival to 50 and 180 days post-weaning occurred in the three experiments. Yard weaning was not superior to any of the producers’ normal paddock-weaning practices, however, favourable seasonal conditions in early 2010 prompted high growth rates in the paddock-weaned Control animals relative to those achieved by the yard-weaned animals. Further research is required to determine the optimum duration of confinement and ration (including composition and method of delivery). This work should include comparisons of the behaviour of paddock- and yard-weaned animals and model production benefits versus economic costs for a range of production systems and market scenarios.