Withholding Periods & Export Slaughter Intervals in relation to seed dressings which are grazed or cut for silage or hay and fed to livestock.
When a winter broadacre crop grown with treated seed is grazed, cut for silage or hay and later fed to livestock, both Withholding Periods (WHPs) and Export Slaughter Intervals (ESIs) must be considered — even though the original treatment occurred at sowing.
For seed dressings (seed treatments) in winter broadacre crops, withholding periods (WHPs) are usually not required for grain production. However, grazing or cutting for silage or hay production, restrictions may apply, depending on the product.
Critical difference: WHP vs ESI
- WHP (Withholding Period):
Focuses on domestic food safety (grain, meat, milk) - ESI (Export Slaughter Interval):
Focuses on export market compliance
You can legally meet a WHP but still fail export residue limits if the ESI isn’t observed.
Legal and practical requirements
- WHPs are legally enforceable and must be followed
- They are product-specific and formulation-specific
- You must not assume one seed treatment has the same WHP as another
Export Slaughter Interval (ESI) — Seed Dressings in Winter Broadacre Crops
- What an ESI actually covers
- The Export Slaughter Interval (ESI) is the minimum time between a chemical application and the slaughter of livestock intended for export markets. It is set to protect compliance with international residue limits, which are often stricter than domestic standards.
Before cutting for hay
- Check label via APVMA
- Confirm:
- Grazing / fodder restriction period
- Only cut hay after this period expires
Before feeding hay
- Ask:
- When was the crop sown?
- When was it cut?
- Was it inside WHP?
- If uncertain → treat as potentially high residue feed
Take Home Message
Hay from seed-treated crops is only safe if timing is right
- Cut after grazing WHP → safe to feed
- Cut too early or contains treated seed → do NOT feed
Livestock exposure changes everything
- Grain = low risk (time has passed)
- Hay/grazing = higher risk (early exposure)
ESI starts when feeding stops — not when crop was grown
- Always apply the ESI from the last day of feeding
- When in doubt → use the longest ESI
