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  • Writer's pictureSandra Witt

Baytril ... Truth & Consequences

​​Most of us are familiar with Baytril; some even claim it to be the ‘cure all’ … of all the medications available for birds this one is the one most inappropriately used. Used properly it’s a very useful medication but usually is incorrectly dosed and often used when it shouldn’t be.

Baytril is actually a brand name for enrofloxacin. Enrofloxacin is sold by the Bayer Corporation under the trade name Baytril. It is currently approved by the FDA for the treatment of individual pets and domestic animals in the United States. There are other brandnames for enrofloxacin, in Australia it’s known by Enrotril. All brands of enrofloxacin oral syrup in Australia are the same strength. ‘Enrotril’ and ‘Baytril’ oral syrups both contain enrofloxacin at a strength of 25mg/ml.

Enrofloxacin belongs to a group of antibiotics called fluoroquinolones; another antibiotic in the same group is ciprofloxacin which is often referred to as ‘cipro’. What does this group of antibiotics do? Fluoroquinolone antibiotics work by interfering with the function of an enzyme that bacteria needs to replicate itself called DNA gyrase. This group of antibiotics have excellent ability to fight against mycoplasma, which is the principle agent of airsac disease. They are effective against most of what are referred to as gram-negative bacteria (like Salmonella, which causes the disease Paratyphoid, and E. Coli).

Fluoroquinolone antibiotics are, however, less effective against ‘gram-positive’ bacteria (such as Streptococcus) so Baytril is a poor choice of an antibiotic for those types of infection. Fluoroquinolones do have some anti-Chlamydial properties; Chlamydia commonly causes eye colds, dirty ceres and deeper infections of the respiratory tract and airsacs. Although treating Chlamydia infections with fluoroquinolones may help the symptoms, but this group is not as effective at actually clearing these organisms as doxycycline. Baytril has no affect against fungi, viruses, canker or parasites.

When SHOULD Baytril be used? Please remember that Baytril is a prescription medication that should only be used after talking to your veterinarian. It should be supplied BY the Veterinarian along with the proper dose for your bird and the conditions under which it’s being prescribed. Many bird owners just want medication, but are reluctant to pay for veterinary advice on the correct way to use that medication. Baytril is a good example of this. It is common sense and logical that Baytril is used when an infection sensitive to it is diagnosed. Again, Baytril is not a good first-line treatment for respiratory infections caused by Chlamydia because while it may reduce symptoms, it is not as effective at actually clearing the organism from the body, and it causes ‘collateral damage’ by killing a lot of good bacteria. Only approximately 15% of Streptococcal strains are sensitive to Baytril so it is not a good choice for this type of infection. Baytril is widely distributed throughout the body and has good tissue penetrating properties. It is thought to actually achieve higher tissue concentrations than blood concentrations. Because of this property it is a good antibiotic choice for gram-negative bacterial infections (in particular Salmonella) and some respiratory infections particularly those due to Mycoplasma. As always, it is worth taking a bit of your veterinarians time and spending some money on diagnosis to see if an antibiotic is part of the answer in controlling a health problem and to see if that antibiotic should be Baytril or another better suited to treat the problem. Lower doses have been found to not be effective against most infections.

​​So what IS the correct dose?

This is the biggest area where I see issues with Baytril. Administering the correct dose is critical for the medication to work properly. Here are a couple of things you need to consider when using Baytril (or any prescription medication).

FIRST ... You need to know the strength of the medication you have in your posession.

  • The strength of Baytril and all other oral syrup brands of enrofloxacin in Australia is 25 mg/ml.

  • In the US, the strength from a Veterinarian is usually 50 mg/ml.

  • You can actually purchase Baytril online at different strengths that are sometimes difficult to convert.

  • A 10% solution has 100 mg of active ingredients per milliliter (ml)

  • A 2.5% solution has 25 mg of Enrofloxacin per ml.

SECOND ... You need to know the weight of your bird.

The dose of Baytril in birds is typically 10-30 mg/kg given orally twice daily.

The dosage math is as follows:

Take the [weight of the bird in kilograms] X [dosage] / [medication per ml or cc]

So if:

... your bird weighs 500 grams and

... you want to give 10 mg/kg and

... the strength is 100mg per ml


500/1000 = .5 X 10 / 100 = 0.05 ml is the proper dose (which is really small because the strength of the solution)

If the strength is from your VET in the US then:

500/1000 = .5 X 10 / 50 = 0.10 ml is the proper dose

If the strength is 2.5% or 25 mg/ml then:

500/1000 = .5 X 10 / 25 = 0.2 ml is the proper dose

BIG difference in dosage as you can see and it all is based on the strength of the solution. Cautions:

  1. Treating birds with Baytril for more than 4 days almost invariably causes a yeast infection. There are always a low numbers of yeasts in the bowel, but their numbers are kept in check by ‘good’ bacteria. Antibiotics kill good and bad bacteria and with nothing to keep them in check, yeasts will quickly multiply leading to the development of green and watery droppings.

  2. Baytril can interfere with cartilage deposition on the surface of young growing joints leading to permanent deformity. This side effect is dose dependent so young nestlings should only be treated with extreme caution and obviously only when necessary. When treated, they must be dosed accurately.

  3. Treating hens that are about to lay with Baytril has been associated with the embryos in those eggs subsequently dying.

  4. Treating fungal infections with Baytril makes them worse.

  5. Treating sick birds in the absence of diagnostic work can waste time treating the wrong problem while disease advances; medication can subsequently interfere with test results that are done.

  6. Treating with Baytril should not part of a routine health management program. Medication should not be used to prevent disease. Baytril has no preventative properties; it will kill organisms that are sensitive to it which are present when the dosage is administered. If birds are re-exposed to the organisms the day after the treatment stops they will likely be re-infected.

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