Advantages of Pasture Manipulation

Summary

Grasses such as barley and brome do not provide good quality spring feed for sheep. As well as limiting livestock productivity during spring, grass seed contamination of the skin and eyes of sheep can cause animal health and welfare issues and reduce carcase value.

This project aimed to demonstrate the advantages to producers of pasture manipulation to improve livestock productivity, by comparing the impact of late and early pasture manipulation to non-manipulated pasture.

Pasture manipulation produced positive financial impacts, improved sheep productivity and improved the following years' pastures. Early manipulation had the biggest impact on feed quality, which enabled producers to extend the season. This created up to 16 days of additional grazing, worth an additional $42 a hectare on average.

Objectives

The aim of this project was to demonstrate the advantages of pasture manipulation in winter to sheep enterprises in Western Australia over a three-year period. Feed tests were taken throughout spring to determine the impact of the timing of winter manipulation on pasture species composition, feed quality and quantity. Economic analysis was conducted to show the overall impact on enterprise productivity and profitability.

Key findings

Pasture manipulation led to:

• increased the percentage of clover and decreased barley and brome grasses
• increased benefits to sheepmeat and wool productivity, potential stocking rates and pasture intake
• valuable additional grazing time at the end of spring
• a decreased need to spray top to control grass seed set.

Pastures manipulated in early winter regained substantial biomass throughout the season, producing high quality, abundant spring feed.

Despite the benefits to animal productivity and pasture growth, the project showed that manipulation may not be profitable for every enterprise, as some will have large costs associated with removing feed especially in early winter. The cost of removing early-season feed averaged $108/ha, while removing late in the season was a $59/ha cost.

Benefits to industry

The project findings have equipped producers with better knowledge and skills regarding pasture manipulation. The data collected, combined with the experiences of producers who hosted the trials, can be used to inform and guide producers' decisions to develop a pasture manipulation or weed management plan.

Based on their production aims, producers can choose from the practices demonstrated in this project – early, late or no manipulation (which necessitates spray topping in spring) – taking into account the economic impacts and expected impact on species composition and sheep productivity.

MLA action

MLA will investigate further research into clarifying results of this project and include other outcomes of pasture manipulation, such as:

• soil nitrogen and soil disease impacts
• increased clover content and decreased grasses in subsequent pastures
• increased carrying capacity
• decreased need to re-sow pastures after a cropping cycle.