Project Overview

This MLA-GRDC Partnership Producer Demonstration Site (PDS) project is demonstrating the untapped grazing potential of crop stubbles and showing how targeted, active management can reduce reliance on live export while supporting a shift toward the more profitable prime lamb market.

The project runs in two stages: Stage 1 focuses on demonstrating the grazing potential of various stubble types, while Stage 2 will introduce and demonstrate an economically optimised stubble grazing strategy for finishing lambs. Year 1 results from Stage 1 trials across barley and canola stubbles have confirmed that active stubble grazing management delivers measurable liveweight performance benefits, and that liveweight monitoring is a more reliable management tool than visual assessment or feed testing alone.

By showcasing practical stubble grazing strategies, the project aims to help mixed-farming businesses in the Great Southern improve livestock performance, increase whole-farm profitability, and better integrate cropping and livestock systems.

Background and Rationale

The potential cessation of live sheep exports presents a significant challenge for producers in the Great Southern region, where wool-focused Merino enterprises dominate. However, research indicates that, when managed effectively, Merino prime lamb production offers a viable and profitable alternative (Young et al., 2020).

This opportunity is strengthened by the continued expansion of cropping in the region. Short-term grazing of crop stubbles has been shown to support high lamb growth rates (Thomas, 2018), yet most producers continue to use a “set and forget” approach to stubble grazing. Modelling and producer experience demonstrate that a more active strategy, where lambs are prioritised and rotated through paddocks to selectively graze higher-quality stubble, delivers superior outcomes.

Maintaining lamb growth rates above 140 g/head/day is critical. Once growth falls below this threshold, lambs should be moved to the next paddock, with lower-priority mobs (such as adult ewes or retained wethers) following to fully utilise remaining feed. For these lower-priority mobs, grazing remains profitable until liveweight change declines to approximately -40 g/head/day (John Young, pers. comms).

Despite widespread summer stubble grazing, fewer than 15% of mixed-farm producers are estimated to actively manage grazing intensity and timing. Research from Murdoch University suggests that producers often underestimate stubble feed value, with sheep continuing to gain weight even when stubbles appear visually depleted (Amelia Gooding, pers. comms, 2024). Year 1 trial data from this project support this finding.

Project Objectives

By May 2028, this project will establish eight demonstration sites across the Great Southern region, engaging 15 core producers and 75-150 observer producers to:

• Demonstrate sheep performance across five crop stubble types over multiple seasons, generating reliable data to improve whole-farm nutritional modelling and management decision-making.

• Test and demonstrate active stubble grazing strategies that increase liveweight gain, extend grazing days per hectare, and reduce supplementary feeding requirements compared with conventional set-and-forget approaches.

• Quantify the whole-farm economic value of active stubble management, including the effects of stocking rate, crop area, and sheep class on stubble utilisation and profitability.

• Develop and distribute practical stubble grazing guidelines for core and observer producers, including clear decision points for stock movement and supplementary feeding.

• Achieve measurable adoption outcomes, with 90% of core producers and 50% of observer producers reporting increased knowledge and confidence in stubble grazing management, and participants having implemented or planning to implement an active grazing strategy.

• Deliver annual field days, webinars, and workshops to share results and support broader adoption across the region.

Year 1 Results (Summer 2025-26)

In the first season, three paddocks were monitored across three host farms in the Great Southern: two barley stubble paddocks grazed by Merino ewes, and one canola stubble paddock grazed by Merino wether weaners.

Liveweight performance

At the barley sites, ewes achieved initial liveweight gains of approximately +100 g/head/day. Performance peaked at around 20 to 30 days of grazing before declining as feed quality diminished. Ewes grazed for approximately four to five weeks without supplementation before net liveweight loss was recorded.

At the canola site, wether weaners grazed for approximately four weeks without supplementation before net liveweight loss was recorded, a comparable result to the barley trials despite substantially lower feed-on-offer, as canola grain is inaccessible for grazing.

Selective grazing and the limits of feed testing

Feed testing confirmed a clear nutritional hierarchy at the barley sites, with grain the highest-quality component, chaff offering moderate value, and stem largely ignored by ewes throughout both trials. Despite measurable differences in chaff and stem quality between the two barley sites, liveweight performance was similar during the early grazing period. Sheep consistently targeted the best available feed first, meaning average paddock feed samples did not reliably reflect what animals were actually consuming. Weekly liveweights proved a more accurate guide to animal performance than feed tests or grain counts alone.

Mob structure and paddock utilisation

Where the trial mob was split across a shared fence line, strong social cohesion between the two groups concentrated grazing along the boundary, leaving outer paddock areas significantly underutilised despite available feed. The intact mob at the other barley site grazed the paddock consistently across its full area. This finding suggests mob structure can substantially affect how effectively a stubble paddock is utilised, independent of feed quality or availability.

Economic modelling

Preliminary whole-farm modelling indicated that as stubble availability per DSE increases, reliance on the stubble resource increases and supplementary feeding requirements decline. Where availability is low, a higher proportion of feed is consumed, and significant supplementation is needed to maintain performance. A full economic analysis is available for producers wanting to examine these interactions in more detail.

Looking Ahead

Stage 1 trials will continue in Year 2, extending monitoring to wheat, faba bean, and lupin stubbles across additional demonstration sites alongside continued barley and canola trials. Economic modelling will translate field results into whole-farm profitability figures that producers can apply to their own systems. Stage 2, focusing on economically optimised strategies for finishing lambs, will be introduced when producers are ready.

Observer producers are invited to join the project network to access trial updates, attend field days and webinars, and take part in workshops on applying economic modelling tools to their own farming systems. A workshop will be held on 22 July 2026, contact Southern Dirt to register your interest in attending .