Antibiotics · Prescription (Rx)
Zactran withdrawal time for cattle
gamithromycin. Used for bRD treatment and control — single-dose macrolide.
Slaughter withdrawal
35 days
| Route / formulation | Slaughter withdrawal | Detail |
|---|---|---|
| Subcutaneous injection (single dose) | 35 days |
Milk & dairy: Not approved for female dairy cattle 20 months of age or older; no withdrawal established for pre-ruminating calves.
Zactran is a single-dose macrolide in the same role as Draxxin — BRD treatment and control — but with a substantially longer slaughter withdrawal: 35 days versus Draxxin’s 18. A generic gamithromycin was approved by FDA in recent years, carrying the same figure.
The practical implication: if there is any chance the animal ships within five weeks, the macrolide you pick matters as much as whether you treat at all.
What the label requires
- Slaughter withdrawal: 35 days from the single dose.
- Nearly double Draxxin’s hold for a similar indication — check your marketing window before choosing.
- Generic gamithromycin carries the same withdrawal; confirm on the bottle.
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: FDA label (DailyMed).
Never ship a treated animal by mistake
Log a treatment in HerdCommand with its withdrawal days and the animal carries a hold flag until the date clears — and the sale workflow warns you before a flagged animal ends up on a load. Works from the phone in your pocket, at the chute.
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Common questions
How long after Zactran can cattle be slaughtered?
35 days after the injection, per the U.S. label. Day zero is treatment day, so an animal treated June 1 clears July 6.