This is the most important decision in the management calendar. Lactation and growing lambs provide a major boost to animal demand that can be aligned to peak pasture supply to increase total production and reduce risk and costs.

Guidelines for the optimum time of lambing have been developed and can be related to the length of the growing season:

  • Self-replacing Merino flocks: lambing 3–4 months before the end of the reliable growing season is about the optimum. Lambing later allows more ewes to be run, but weaner management has to be excellent as they will be lighter when the feed quality falls. If the decision to lamb later is made, supplementary feeding to weaners is more cost effective than feeding pregnant or lactating ewes during the low pasture growth periods.
  • Prime lamb flocks: lambing 3–5 months before the end of the reliable growing season can produce a better result because it maximises the chance of finishing the lambs on pasture which is often the cheapest source of energy and protein.

The Lifetime Wool project has ewe management guidelines, tools and tips and background research results with economic analyses for sheep producers across southern Australia.

Many farms run sheep and cattle as well as a cropping enterprise. In such cases, the feed demands of the beef enterprise and the labour demands of the cropping program need to be factored in, which may alter the optimal time of lambing.