Rest Based Grazing System
Wyloo Station
Lead: Shanon Thompson
Region: West Pilbara, Ashburton River Region
Hectares: 200,000
Environment: A harsh yet resilient landscape consisting of native grasses, shrubs, and scattered trees across broad open plains, rocky ridges, and alluvial river flats.
Challenge Identified: Improving the management of heifers and second calvers, while ensuring optimal pasture availability and improved land condition.
Status: Completed, with continuation within Wyloo’s enterprise.
Approach
Shanon’s goal after identifying the challenge is to give the business more choices in tight seasons. The project centres on a 5-paddock rest-based grazing system in conjunction with controlled mating of the heifer age group. This system relies on accurate monitoring of animal performance and land/pasture condition. The theory behind this is boosting reproductive rates, calving at the optimal time with the highest-risk age group, and maintaining a chain of paddocks that has improved pasture availability and overall land condition.
Controlled mating allows Wyloo to wean this section of the enterprise at any time. This gives them greater flexibility to meet seasonal demands and alleviate pressure on the land. It also allows them to eliminate a second mustering round, reducing labour and time costs.
Identify and survey the areas deemed best suitable for the five paddock system.
Install the necessary fencing, upgrades to water points where needed, establish monitoring sites (GCG monitoring tool), and set up an Optiweigh system.
Induct the first group of 210 heifers in March 2025. They averaged 390kg, and 7 bulls were joined to them for a 60-day mating period.
Monitor the paddocks for pasture and animal health indicators, and cross-reference these observations with the Optiweigh data (average daily gains).
Rotate the heifer age group through the paddocks in conjunction with paddock observations, Optiweigh data, and calving times.
When necessary, alleviate carrying capacity by shifting or selling PTE (preg-tested empty) heifers.
Key Insights
1
Optiweigh data provided real-time information on animal performance, reinforcing our decision-making and giving us confidence. It also saved on mustering time and alleviated weight losses on having to bring animals into the yards to collect information on liveweight.
2
PEN’s professional development program for the Lead’s produced better decision making abilities for the business. Practicing the new skills on the research project helps consolidate learning by applying knowledge and building the capability to pass it on to others.
3
Even during a dry season, Wyloo was able to observe a good vegetation response with limited rainfall in paddocks ahead of the mob. Limited information at this time on vegetation response behind the mobs, but fingers crossed for more rain soon.
4
Managing these heifers separately allowed Wyloo to make strategic decisions regarding grazing pressure as the season progressed, which in a year like 2025 was just as important for them as conception rates.
Impact & Results
2025 was unfortunately a dry season, following a few consecutive dry seasons at Wyloo Station. This resulted in less meaningful data being collected regarding conception rates. As is always the case with research projects running in agriculture, we are at the mercy of Mother Nature. We will keep you posted with further updates on 2026 conception rates on the next line of heifers, as well as the reconception rates from the 2025 heifer age group when they become available.
What was discovered:
- The rest-based system ensured animals had pasture available even during a dry season.
- The Optiweigh unit was well utilised by the animals (up to 75%), and the data collected was used to reinforce decisions made on animal and pasture observations made in the paddock.
- Control mating gives you more options; removing poor performers, setting animals up to calve at the optimum time and being able to wean according to season to influence reconception rates.
- We’ve reinforced our confidence in the controlled mating system to gain insight into where and how we can improve reproduction, as well as overall benefits to our land and business.