As harvest ends, summer fallow management will become the priority to conserve soil moisture, soil nitrogen and minimise the risk of increased disease and insect pressure associated with a green bridge in the following season.
Grazing before summer spraying
Depending on the rain, and what weeds germinate and grow, you might first get some grazing value from the weeds.
MLA supported research conducted by Southern Farming Systems measured the nutritional value of summer weeds over their growing months. The work is about to be published, but you can view Cam Nicholson’s (Nicon Rural) presentation at the 2019 Best Wool Best Lamb Conference where he discussed the main summer weeds and their value (or not) to livestock. By understanding the weed value and what stock need you can make decisions about whether to graze before using chemical control.
Grazing after summer spraying
When planning summer spraying and before grazing, consider withholding periods (Table 1) and be aware of Export Slaughter Intervals (ESI); the time required on clean feed prior to export slaughter, on new chemicals.
Table 1. Label grazing recommendations for summer fallow chemicals
|Withholding period||Oxyflurofen||Pyraflufen||Butafencail||Saflufencail + |
|Cereals||Do not allow livestock to graze treated weeds||All crops: 7 days. Don’t graze treated cotton||6 weeks||6 weeks||14 days||Not required.|
Don’t graze treated cotton
|Pulses||4 weeks||ns||7 days|
|Other crops||ns||ns||5 weeks|
|ESI||ns||ns||ns||ns||30 days||Not required|
ns – not specified
Grazing withholding periods apply to stock destined for the domestic market, but some export markets apply different standards. If unsure, check with your agent to ensure your stock will comply with their intended market.
Managing breeding ewes in containment areas
Once grain has run out and green pick eaten or spray fallowed, the nutritional value of cereal stubble falls markedly (Table 2).
Table 2. Average feed value of cereal crop components
|Feed value||Grain||Green||Standing straw||Trash|
|Digestibility (DMD %)||82 – 87||59 – 73||38 – 40||40 – 41|
|Metabolisable energy (MJ/kg DM)||12.7 – 13.2||8.5 – 11||5 – 5.3||5.3|
|Protein (%)||9.5 – 13.5||15.9 – 18.7||1.2 – 2.8||2 – 4|
Source: Grain & Graze
Containment areas can be used as a regular strategy during autumn when stubbles are longer sufficient, to protect paddock ground cover and control the increasing nutritional requirements of pregnant ewes.
A successful operation will cost effectively achieve high sheep health and welfare, and optimise lamb marking rates.
The new MLA guide ‘Managing breeding ewes in containment areas’ by Dr Susan Robertson, Charles Sturt University, steps through the recommended management of ewes in containment to achieve the best outcomes.
Another resource is Agriculture Victoria’s ‘Drought Feeding and Management of Sheep’ (2018). For a hard copy contact Alison at BCG.