Effects of ewe fecundity on productivity, profitability and emissions in prime lamb systems

Whole farm systems analysis from the WFSAM project

The study was conducted using real data from a self-replacing prime lamb enterprise in southern Australia with high fecundity ewe genotypes. Increasing ewe fecundity from 1.0 to 1.5 lamb per ewe at birth increased production by 27% and reduced net farm emissions by 21% for the same long-term stocking rate.

An economic analysis compared the relative merit of the same farm, with high-fecundity ewes, with a baseline system that represented a typical prime lamb enterprise in the region and an additional system comprising ewes with high fecundity at a lower stocking rate.

Increasing ewe fecundity increased whole-farm profit, but risk, or variability in farm profit also increased. Decreasing stocking rate for the high-fecundity system reduced annual operating profit and net present value at a 5% discount rate, but had less risk compared with the higher stocking rate system.

Under the high fecundity strategy, potential revenue from carbon credits was relatively small. However, whole farm returns were higher when compared with the low fecundity system regardless of whether carbon credits were included, suggesting that high fecundity ewes may provide a potential avenue for producers to increase production and profit, as well as reduce carbon emissions.

Primary researchers


Harrison MT, Cullen BR, Rawnsley RP, Eckard RJ (2013). Does increasing ewe fecundity reduce whole-farm greenhouse gas emissions intensities? 20th International Congress on Modelling and Simulation (MODSIM2013), Adelaide, 1-6h December 2013.

Harrison MT, Cullen BR, Jackson T, Rawnsley RP, Ho C, Cummins L, Eckard RJ (2014). Increasing ewe genetic fecundity improves whole-farm production and reduces greenhouse gas emissions intensities 1. Sheep production and emissions intensities. Agricultural Systems 131, 23–33, http://dx.doi.org/10.1016/j.agsy.2014.07.008.

Ho C, Jackson T, Harrison M, Eckard R (2014). Increasing ewe genetic fecundity improves whole-farm production and reduces greenhouse gas emissions intensities: 2. Economic performance. Animal Production Science, 54, 1248-1253, http://dx.doi.org/10.1071/AN14309.

More information