Summer Pasture Management
Summer Pasture Management
Manage your farm to a plan
Having a plan reduces stress, and helps avoid indecision that often arises in dry summers.
Plan for different scenarios. Identify and document key decisions to make, targets and trigger points i.e. different feed budgets can be prepared for the summer period.
One plan might be an optimistic summer growth scenario, another plan would cater for less than favourable pasture growth conditions, which demands early decisions to reduce feed demand.
If your farm experiences summer dry periods then there needs to be a plan for a prolonged dry period requiring supplement feeding until the rain arrives and pasture growth resumes.
Use weekly farm walks to monitor both farm pasture cover using a rising plate meter and cow condition score. Update against feed budgets regularly.
The key at this time of year is to prevent pasture going to seed.
Trials show that achieving target grazing residuals consistently throughout spring will impact positively on summer milk production.
Production can only have come from a combination of pasture quantity and quality, which comes from maintaining grazing residuals throughout the whole season.
This is advantageous in several ways:
i) There will be higher utilisation of pasture.
ii) Little dead material accumulates in the base of pasture.
iii) Most developing seed heads will be removed by grazing before they emerge from the stem of the tiller.
iv) The ryegrass plant will return to producing new vegetative daughter tillers and leafy pasture.
v) The ryegrass plant will retain a larger root mass into the summer allowing better access to soil moisture.
Apply nitrogen fertiliser to encourage further vegetative growth and survival of daughter tillers.
Get on a long rotation before low soil moisture reduces growth
Use the last of the pasture surplus in May / June to slow down the rotation length to between 30 and 35 days before the dry period arrives.
Tiller emergence occurs every 32 â€“ 35 days over summer. At rotation lengths longer than this, dry-matter will accumulate as dead dry leaves which if not eaten will decompose when it rains.
The length of the summer round should be similar to the expected length of the dry period e.g. a 30 to 40 day dry period will need a rotation length of about 30 to 40 days.
Hold this round until significant autumn rains occur which reduces the soil moisture deficit. Thia will vary with soil type.
Ensure that the increase in average cover on the farm is due to the longest paddocks getting longer, rather than higher residuals being left behind.
By getting onto this long round early you can maintain good pasture utilisation while carrying a feed-wedge of quality pasture forward into the summer months when pasture growth is expected to reduce.
Deferred grazing is a flexible variation on surplus pasture management in early summer that is used as an alternative to mechanical harvesting to:
Maintain pasture utilisation, target grazing residuals and pasture quality on pasture not being mechanically harvested or deferred
Help extend the summer grazing rotation, in advance of reduced pasture growth soil moisture deficit
Deferred grazing has advantages of flexibility and cost avoidance for a small percentage (e.g. less than 10% of the farm area).
As growth rates decline, the deferred pasture needs to be fed as a standing crop to support cow intake while maintaining and/or extending a long rotation, postponing the need to feed silage.
In a dry summer deferred pasture will never overcome a large feed deficit, and needs to be fed off early while quality of this feed is reasonable. Hence deferred pasture might only skip one grazing rotation.
In a wet summer the deferred pasture might not be grazed for several rotations, but needs to be grazed before early autumn rains cause decay, and to allow the reseeding effect to proceed.
Quality of deferred pasture will be low compared to well grazed pasture, and regrowth will be slow. Weed grasses can be major problems. When rain comes the dead material will decay, and be unpalatable.
A summer forage crop needs to yield at least 12 tonnes DM/ha and be managed to achieve high utilisation to be profitable. Use the crop to lengthen grazing rotation length while maintaining cow intakes.
Be wary of the effects of the reduced grazing area available on pasture cover during the 60 to 80 days that the crop is growing, and during the 40 to 60 days before the new pasture is re-established.
In a prolonged dry period, when pasture cover and residuals drop too low to support milking cows, supplements may be fed to prevent overgrazing.