Key Points
• Predict monthly pasture growth in kg DM/ha/day for a range of weather patterns.
• Continually match animal feed demand to predicted feed supply.
• Use partial budgets to assess the benefits and costs of options to match supply to demand.
Why is tactical control of grazing stock numbers important?
Normal fluctuations in seasons, pasture growth and market prices mean that you need to review the numbers in each herd or mob continually to:
• Ensure that the cattle have the required feed available to meet growth targets (productivity);
• Reduce the risks of pasture damage and other adverse environmental impacts (sustainability); and
• Maximise your potential to make profit (profitability).
Predicting the amount of pasture that will be available and comparing it to animal performance targets enables you to match feed demand to supply to achieve maximum production.
Forecasting the available feed supply across the farm enables you to take action to increase or decrease stock numbers accordingly. When excess pasture is predicted, additional stock may be purchased or feed can be conserved for times of shortage.
Excess pasture is often under grazed and under utilised because ungrazed pastures are considered a feed reserve (‘standing hay’) that can be used as a risk management strategy.
Reserving standing feed may not be the most productive and profitable strategy as the value of water and soil nutrients used to grow pasture is wasted while the pasture deteriorates in quality. In the same way, valuable resources can be wasted by choosing not to increase stock numbers or conserve excess feed as hay or silage. The question is how to balance the tactical grazing options to give the highest possible profit, while allowing you to build confidence and manage the risks comfortably.
Controlling stock numbers to increase and decrease grazing pressure at appropriate times is also essential to improve the growth capacity of long-term pastures, and to avoid degrading pastures and soil. Varying grazing pressure through stock manipulation can be used to improve the growth of long-term pastures and to avoid pasture and soil degradation.
• Moderate overgrazing reduces leaf area and lowers the carbohydrate stores in the roots. These are needed to maximise pasture regrowth.
• Severe overgrazing can result in the death of desirable plant species, weed invasion, reduced water use efficiency and topsoil loss through erosion.
• Undergrazing can also cause reduced pasture growth because of increased shading and senescence (older leaves dying-off), loss of preferred pasture species and lower animal productivity through poorer feed quality.
You need to allocate each mob to the best pasture option (based on quantity and quality) for the particular production targets set for them, across the farm, to ensure the greatest profit potential from the enterprise. For example, allocate dry cows in good condition to poorer quality pastures and young growing stock destined for sale to better pastures.
How does this article assist you?
This article describes a process to predict the number of available days of grazing based on current herd requirements and the pasture growth expected, so that stock numbers can be adjusted accordingly. An approach to controlling the risks of over- or under grazing is provided to ensure that animals and pastures are maintained in the best condition for long-term sustainability of the enterprise. The chances of financial loss in poor years are reduced while the profits in good years can be increased.
Grazing pressure is managed by changing the:
• Numbers, type and growth targets of livestock on pasture;
• Numbers, type and growth targets of livestock fed off pasture (such as in a feedlot or on a feeding pad), but available for transfer back to pasture; and
• Pasture-based feed supply and quality through the year using supplements, seasonal feed transfers, and cutting or boosting growth. Growth can be manipulated by applying fertilisers, such as nitrogen, phosphorus and potassium, during growth periods and at critical times of rainfall.
Normally this requires the continual adjustment of stock numbers and pasture management as pasture growth varies, and perhaps periods of supplementary feeding when pasture growth rates are low. The costs and benefits of options to adjust pasture supply and demand vary throughout the year and between years. Forward planning, with routine updating of partial budgets to assess available options, will enable timely and effective decisions to be made that are based on current costs and anticipated benefits.
The strategy of continual adjustment to maintain pastures within limits that allow maximum pasture growth and quality cannot be applied continuously to annual pastures or to some species of perennial pastures. These need to set seed for regeneration of plants in following years. Also, in locations where there is only one or perhaps two short growing seasons, low-quality dry standing pasture can be the most economical feed source during several months of the year.
