Best management practice of ryegrass and managing the residual height throughout dry periods is critical to enhance persistence of pasture.
The key points for managing grazing residuals during dry conditions are: Do not over-graze if possible, maintain the residuals at 4-6 centimetres. Cows tend to graze down below this in drier conditions, so grazing needs to be restricted. Grazing to 2cm, for example, will significantly reduce yield in the following rotations. Aim to maintain some green material throughout drier times (e.g. green stem, pseudo stems), as this will help survival and regrowth. The presence of some pasture cover by maintaining residuals at 4-6cm creates a more favourable microclimate near the soil surface than when grazed below this. The microclimate can help retain soil moisture close to the surface and create protection from extreme soil surface temperature.
To achieve these aims is a significant challenge on dairy farms with high stocking rates when the rainfall and temperature is not sufficient to support pasture growth.
It is necessary to have a set strategy or plan to avoid over-grazing. The approach to managing residuals in dry conditions is, in essence, similar to that adopted to avoid pugging under waterlogging conditions in winter.
The strategy is to keep the cows in a reduced area (sacrifice paddock or on a feed pad) where they can be fed, and graze only the paddocks where pasture is at 2.5-3 leaves.
Paddocks suitable for use as sacrifice paddocks should have the following: Good stock water access. Good shade. Close proximity to the dairy. Been previously identified for renovation.
By feeding out in the sacrifice area or feed pad, the cows will be less hungry when entering a new strip of grass, making it easier to control the grazing intensity and leaving a residual close to the target.
A good estimation of pasture pre-grazing cover and knowledge of the paddock dimensions is also essential in order to allocate pasture more accurately and achieve the target residuals.
This management increases the persistence of pasture sward, which will be in a much better position to recover from the dry period once the first significant rainfall event occurs.
This may mean that paddocks need to be rested for an extended period.
Developing a feed budget will help to calculate and plan how much feed will be required to feed the herd in the coming months.
Dairy Australia's Feed Tools at website is a useful tool to determine feed requirements for the herd.
Ensuring there is enough feed for the herd will reduce the risk of overgrazing and ensure pastures recover when rainfall occurs. The feed budgeting fact sheet at dairyaustralia.com.au/feedshortage provides more information on feed budgeting.
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