Dewormers & parasiticides · Over the counter
Ivermectin (Ivomec & generics) withdrawal time for cattle
ivermectin; + clorsulon in Plus products — Ivomec, Ivomec Plus, Noromectin, Agri-Mectin, Bimectin, many generics. Used for roundworms, lungworms, grubs, lice, and mange; Plus products add liver flukes.
Slaughter withdrawal
48 days
pour-on; 35 days injectable; 21 days Ivomec Plus
| Route / formulation | Slaughter withdrawal | Detail |
|---|---|---|
| Injectable 1% (SQ) | 35 days | |
| Pour-on 5 mg/mL | 48 days | |
| Ivomec Plus (ivermectin + clorsulon, SQ) | 21 days | Current label — older charts list 49 days; go by your bottle |
Milk & dairy: Not approved for female dairy cattle of breeding age (no milk withdrawal established) — Eprinex is the pour-on with dairy approval.
Ivermectin’s withdrawal depends entirely on the formulation, and the ordering surprises people: the pour-on carries a longer slaughter hold (48 days) than the injectable (35 days), and the current Ivomec Plus label — the fluke product — is shorter than both at 21 days.
That Plus figure is worth a double-take: plenty of older extension charts still list 49 days for ivermectin-plus-clorsulon products, but the current FDA label reads 21. It is a live example of why the bottle in your hand beats any chart, including this one. Generic ivermectins are label-equivalent, but confirm the number printed on the product you actually used.
What the label requires
- Injectable: 35 days. Pour-on: 48 days. Ivomec Plus: 21 days (current label; older charts say 49).
- The pour-on’s longer hold catches people who assume topical = milder.
- Not for female dairy cattle of breeding age.
- Pour-on dosing is by weight down the backline — underdosing drives both resistance and unpredictable residues.
Always follow the label on your bottle and your veterinarian's directions. Extra-label use — any different dose, route, or frequency — voids the withdrawal above; your vet sets the interval instead, usually via FARAD. When in doubt, hold longer. Label data checked July 18, 2026. Source: Ivomec Plus FDA label (DailyMed).
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Common questions
Why is the ivermectin pour-on withdrawal longer than the injectable?
Absorption through the skin is slower and more prolonged than from a SQ injection site, so tissue residues persist longer — 48 days versus 35. The route changes the pharmacology, and the label reflects it.
My old chart says Ivomec Plus is 49 days but the bottle says 21. Which is right?
The bottle. The current FDA label for Ivomec Plus specifies "Do not treat cattle within 21 days of slaughter." Older charts predate label revisions. When a chart and your label disagree, the label wins — that applies to this page too.