Set trigger points to cope with seasonal variation
MLA & AWI July 31, 2024
Trigger points spark action well before critical feed shortages. For example, if it hasn’t rained by a certain date or pasture availability drops below the targets, producers can change weaning time, sell stock, start supplementary feeding with stored fodder, buy grain for ewes and weaners, or plan to use nitrogen and rotational grazing to boost pasture growth leading up to lambing.
Put a plan in place to meet set targets for animals and pasture using these strategies:
- Identify a pasture quality and quantity target on a particular date — the ‘trigger point’.
- Develop a grazing plan to build feed reserves in identified paddocks and ensure the required pasture will be available when needed.
- Plan paddock allocations using the pasture benchmarks table to check pasture supply will meet animal demand.
Pasture targets** (kg green DM/ha) to meet animal demand at three levels of pasture digestibility (%)
Sheep class
75% digestibility (mainly sown species, actively growing, 30% legume <10% dead)
68% digestibility (volunteer or native species, 15% legume, 20% dead)
60% digestibility (dried off pasture in early summer or mature volunteer/native species)
Dry sheep
400
600
1200
Pregnant ewes
Mid pregnancy
500
700
1700
Final month
700
1200
Not suitable
Lactating ewes
Single lambs
1000
1700
Not suitable
Twin lambs
1500
Not suitable
Not suitable
Growing weaned lambs (% of potential growth)
30% (75g/day) *
400
700
1700
50% (125g/day) *
600
1000
Not suitable
70% (175g/day) *
800
1700
Not suitable
90% (225g/day) *
1600
Not suitable
Not suitable
Source: PROGRAZE®, adapted by AWI and MLA
- Use feed budgeting for short-term and long-term planning. The Feed year plan template tool helps to identify pastures and crops capable of achieving high production outcomes in sheep and shows the times of year they’re at their best, and when there are feed gaps.
- After reviewing the situation at the trigger point, take appropriate action. For example, if stock meet condition score targets and the feed budget predicts enough feed; continue to monitor pasture supply and condition score closely to ensure this remains the case.
- If stock meet condition score targets, but the feed budget predicts pasture supply will not meet their nutritional demands in three months’ time, options include:
- growing more pasture: apply nitrogen to boost pasture supply; assess availability of other paddocks for grazing.
- considering the option of grazing crops.
- reducing stocking rate: re-allocate stock to another paddock, draft off dry ewes, seek agistment for sheep elsewhere, or sell some stock.
- If stock are below condition score targets and it is estimated there will be less than target feed in three months’ time, options include:
- feeding supplements now and growing more pasture.
- reducing stocking rates.
- accepting a lower production level and potential damage to the pasture or soil base.
- If stock meet target condition score and the feed budget predicts a feed surplus in three months’ time, consider agisting or trading extra stock, or conserving fodder for later.