Enrofloxacin for Cow: Uses, Dosing & Side Effects

This information is for educational purposes only. Never give your pet any medication without your veterinarian's guidance. Dosing, frequency, and safety depend on your pet's specific health profile.

Enrofloxacin is a fluoroquinolone antibiotic used in cattle under veterinary prescription. In the U.S., the best-known cattle product is Baytril 100, an injectable formulation labeled for beef cattle and non-lactating dairy cattle. It is not a routine, over-the-counter antibiotic, and federal law prohibits extra-label use of fluoroquinolones in food-producing animals.

This medication is valued because it reaches good tissue levels and can be effective against important respiratory pathogens. In cattle, it is used by subcutaneous injection, not as a casual add-on treatment. Your vet will decide whether it fits the case based on the animal's age, production class, likely bacteria, and food-safety considerations.

Because cattle are food animals, enrofloxacin use also involves withdrawal times, label restrictions, and antimicrobial stewardship. That means the right drug, right animal, right dose, and right duration matter even more than they do in many companion-animal cases.

In U.S. cattle, enrofloxacin is primarily labeled for bovine respiratory disease (BRD) in beef and non-lactating dairy cattle. Label indications include treatment of BRD associated with Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni, with the single-dose label also including Mycoplasma bovis. It is also approved for control of BRD in cattle at high risk of developing disease, again only in the approved production classes.

That matters because not every coughing, feverish, or off-feed cow is a candidate for enrofloxacin. Your vet may choose another antibiotic based on exam findings, herd history, recent antibiotic exposure, culture results when available, and residue concerns. In many herds, treatment decisions are made within a broader BRD protocol rather than around one drug alone.

Enrofloxacin is not labeled for lactating dairy cattle, and extra-label use in food-producing animals is prohibited in the U.S. If a pet parent is caring for a family cow, bottle calf, or small homestead beef animal, it is still essential to follow the same food-animal rules and your vet's instructions.

Enrofloxacin dosing in cattle must come directly from your vet and the product label. For Baytril 100 in beef and non-lactating dairy cattle, labeled single-dose therapy for BRD is 7.5-12.5 mg/kg subcutaneously once. Labeled multiple-day therapy is 2.5-5 mg/kg subcutaneously every 24 hours. The product information also expresses this as 3.4-5.7 mL/100 lb once for single-dose therapy and 1.1-2.3 mL/100 lb daily for multiple-day therapy.

In practice, your vet chooses the exact regimen based on the diagnosis, severity, handling logistics, and the animal's weight. Accurate weight matters. Underdosing can reduce effectiveness and may contribute to resistance, while overdosing raises safety and residue concerns. Because this is a food-animal drug, pet parents should never estimate a dose from internet charts or use leftover medication.

Ask your vet to review the route, injection site, number of treatment days, and meat withdrawal time for the exact product being dispensed. Also confirm whether the animal's production status has changed. A heifer that may enter the milking herd, for example, needs especially careful medication planning.

Many cattle tolerate enrofloxacin well when it is used exactly as labeled, and field data for approved BRD use reported no test-article-related adverse events in one supplemental approval study. Even so, side effects are still possible, and your vet should be contacted if your cow seems worse after treatment rather than better.

Potential concerns with enrofloxacin and other fluoroquinolones include digestive upset, reduced appetite, injection-site irritation, and neurologic signs such as excitability or seizures in susceptible animals or overdose situations. Fluoroquinolones as a class are also associated with cartilage and joint concerns in growing animals, which is one reason careful veterinary oversight matters.

See your vet immediately if you notice collapse, severe depression, tremors, seizures, marked swelling at the injection site, worsening breathing effort, or refusal to eat and drink. In food animals, side effects are only part of the picture. A treatment that is technically tolerated may still be inappropriate if it creates residue or label-compliance problems.

Enrofloxacin can interact with other medications, so your vet should know about all prescription drugs, medicated feeds, supplements, and recent injections before treatment starts. Fluoroquinolones may have reduced absorption when given orally with products containing calcium, magnesium, aluminum, zinc, iron, or sucralfate, although oral use is not the standard labeled route in U.S. cattle.

Class-wide veterinary references also advise caution when enrofloxacin is combined with theophylline, cyclosporine, corticosteroids, and certain other antibiotics. Some combinations may increase side-effect risk, while others may reduce antibacterial effectiveness. In food animals, the bigger issue is often whether a combination fits legal labeling and residue rules.

Because extra-label use of fluoroquinolones in food-producing animals is prohibited in the U.S., pet parents should not mix and match treatment plans from other species. If your cow is already being treated for pain, dehydration, parasites, or another infection, ask your vet to review the full medication list before enrofloxacin is given.