Active ingredient
Florfenicol for Animals: Mechanism, Doses by Species & Brands
Florfenicol is a phenicol antibiotic used in cattle at 20 mg/kg IM repeated after 48 hours, or 40 mg/kg SC once [1]. Some products combine it with an NSAID for respiratory disease with fever — Resflor Gold with flunixin [2] and Zeleris with meloxicam [3].
- Drug class
- Antibiotic (phenicol)
- Sourced doses for
- Cattle
- Brands on this site
- Resflor Gold, Zeleris
Florfenicol dose calculator
Type the strength printed on your own product. Results are calculated in your browser from the cited doses on this page — always check the label of the product you use.
Florfenicol dose by species
What florfenicol is used for
Safety, contraindications and precautions
- Not approved in dairy cattle 20 months of age or older [1].
Brands that contain florfenicol
| Brand | Company | Contains | Market |
|---|---|---|---|
| Resflor Gold | MSD Animal Health (Merck Animal Health in the US) | Florfenicol + Flunixin meglumine | USA (FDA label) |
| Zeleris | Ceva Animal Health | Florfenicol + Meloxicam | Canada |
Frequently asked questions
Have a case in front of you?Ask WeVet — the AI assistant built for veterinarians. Differentials, treatment plans with calculated doses, drug info from trusted sources and SOAP notes.
Ask WeVet about thisMedically reviewed by
Dr. Ravi Baraiya, B.V.Sc.
Veterinarian · Reviewed 2 Nov 2026
References
- Dosages of Chloramphenicol and Florfenicol
Passage read from this source
20 mg/kg, IM, repeated in 48 h; 40 mg/kg, SC, once
Not approved in dairy cattle > 20 months of age
- RESFLOR GOLD — label
Passage read from this source
Each milliliter of sterile RESFLOR GOLD® contains 300 mg florfenicol, 16.5 mg flunixin as flunixin meglumine,
- ZELERIS — Canadian label
Passage read from this source
Active ingredients: 400 mg of florfenicol and 5 mg of meloxicam;
For veterinary professionals. Information supports — never replaces — clinical judgement; always check the current product label and local regulations.