Key Points
• Aim to use 50% or more of green pasture growth to increase livestock production and profitability/ha.
• Base your grazing management on plant growth rate and growth stage for high quality and yield of pasture.
• Use tactical grazing to meet different animal and pasture objectives at various times.
• Manage pastures to ensure adequate rest and regrowth before the next grazing.
Why is efficient utilisation of green pasture important?
The focus of this module is on the utilisation of high quality green pasture. Increasing the use of green pasture grown can be the most cost effective way of lifting the productivity for the majority of beef enterprises. Grazing managers should aim to convert the largest amount of pasture energy and nutrients into saleable beef while leaving pasture residue in the best condition for rapid regrowth. Precise control of grazing pressure and herd structure across a total grazed area can achieve utilisation of up to 50% of green pasture grown. This level is higher than current industry estimates of 30 to 40% utilisation of total green pasture grown.
Intake of green pasture by cattle and consequently productivity is influenced by the height, bulk density, total herbage mass per area and digestibility of the sward. Increasing utilisation can also improve pasture growth and quality, leading to better feed conversion efficiency, increased beef production per unit area and a decrease in unit cost.
The most important factor in improving profitability is identifying the stock numbers (stocking density or head/ha) that the enterprise is likely to sustain when utilisation of high quality (greater than 70% digestibility) green pasture is increased. The number of animals (head/ha) will depend on the nature of the enterprise (breeding and/or trading) but should be sufficient to ensure high utilisation of the pasture grown while maintaining the long-term sustainability of the pasture and the grazing system. To achieve an increase in pasture use, adopt a grazing management approach based on predicted seasonal plant growth patterns:
• Graze enough animals to fully utilise available pasture without depressing animal intake to below target requirements or grazing of new plant growing points.
• Ideally time grazing to begin just before first leaf senescence (dying-off) occurs for desirable pasture species.
• Monitor grazing and stop it before critical limits for minimum pasture mass, height and ground cover are reached.
• Accurately assess the regrowth period before the next grazing occurs by monitoring pasture growth rates and the number of leaves per tiller.
A plant-based approach to grazing management ensures that pasture eaten by cattle during the growing season is of the highest possible nutritional quality (metabolic energy is greater than 11.5 megajoules per kilogram of dry matter or ME>11.5 MJ/kg DM), while giving the greatest opportunity for pasture regrowth following each grazing event.
The aim is to implement the procedures described below across the entire beef enterprise. Investment of time and capital is needed to intensify the grazing system in most beef enterprises. A grazing plan is essential for the progression of paddock sequences around the farm to determine the level of investment that is operationally and economically justifiable. Careful management of less intensively grazed land using the same approach leads to further gains in productivity. The aim is for a sustainable and productive beef production system that maintains weed-free stable pastures and ground cover greater than 70% on flat land and low slopes to reduce run-off, prevent erosion, and improve the quality of water entering waterways.
Pasture mass limits
There are references throughout this module to varying minimum and maximum limits for pasture mass (kg green DM/ha). It is important to understand the reasons for these variations.
• 1,500kg green DM/ha is used as a minimum to maintain good conversion of pasture to beef.
• Grazing below this level to a minimum of 1,000kg green DM/ha will mostly not harm the pasture or its potential rate of regrowth, but animal intake will start to be severely reduced.
• At certain times of the year, for example in autumn, good pasture management requires you to graze below 1,500kg DM/ha. In these cases allocate animals that can tolerate low weight gain or loss of weight such as dry or pregnant breeders.
How does this article assist you?
Application of the principles and procedures in this article and use of the tools will enable you to lift stock numbers and better manage green pasture utilisation on grazed land. This will increase your beef productivity (kilograms of beef per hectare) and decrease your unit cost of production (cents/kilogram beef).
To achieve this you will need to:
• Identify the stock numbers (stocking density or head/ha) that the enterprise will sustain when green pasture utilisation is increased.
• Identify and monitor the most appropriate indicators to time the start of grazing.
• Stop grazing before pasture composition and ground cover are adversely affected.
• Use routine field measurements (pasture phenology, mass and height) to estimate both the number of days’ rest required before the next graze and the amount of pasture mass available.
• Manage grazing pressure to ensure that planned and efficient use of available pasture mass and energy content is achieved before regrowth is grazed.
• Plan the best balance of animal performance and pasture regrowth by grouping and allocating cattle according to their nutritional requirements and determining the grazing sequence and duration for grazing units across each pasture zone.
• Set pasture and animal targets and precision-manage the grazing of all pasture zones to achieve production targets, maintain pastures and prevent soil and environmental degradation.
Principles of pasture utilisation
• Maximum cattle performance is achieved by managing the pasture to maintain mass between 1,500kg and 2,500kg green DM/ha.
• Pastures grazed in green leafy vegetative condition have the highest nutritional quality (ME>11.5 MJ/kg DM).
• Animal intake and pasture quality decline when the mass exceeds 3,000kg green DM/ha.
• Maintaining pasture mass above 1,000kg green DM/ha promotes rapid growth and avoids overgrazing or patch grazing.
