Just found this at http://www.melbournebirdvet.com/baytril-the-myths-and-reality.aspx
BAYTRIL - THE MYTHS AND REALITY
By Dr Colin Walker BSc, BVSc, MRCVS, MACVSc (Avian health)
Most pigeon racers will be familiar with the medication ‘Baytril’. In some circles it has gained the reputation as a veritable ‘cure all’. Yet, of all the medications available to pigeon racers, this is the one that is most often used inappropriately – usually at the wrong dose and often in the wrong situation. Used however in the correct way, it can be a very useful medication. So what are the facts?
What is Baytril?
‘Baytril’ is the brand name of an antibiotic called enrofloxacin. It is available in tablet form, as an injection and also an oral syrup. The oral syrup can be given directly to the mouth or dissolved in the drinking water. Enrofloxacin is also sold under other brand names in Australia, notably ‘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 and therefore from a therapeutic point of view are identical. Enrofloxacin belongs to a group of antibiotics called fluoroquinolones. Another antibiotic in the same group, used more overseas, is ciprofloxacin which is often abbreviated to ‘cipro’ by pigeon fanciers.
What do these antibiotics do?
Fluoroquinolone antibiotics such as enrofloxacin (eg ‘Baytril’ and ‘Enrotril’) and ciprofloxacin work principally by interfering with the function of an enzyme called DNA gyrase that is required for a bacteria to replicate itself. These antibiotics have excellent activity against mycoplasma (the principle agent of ‘airsac disease’). They are also effective against most of what are called gram-negative bacteria which includes Salmonella (which causes the disease Paratyphoid) and E. Coli. They are, however, less effective against what are called ‘gram-positive’ bacteria (such as Streptococcus - ‘Baytril’ is therefore a poor first choice of an antibiotic for this type of infection). Fluoroquinolones do have some anti-Chlamydial activity. Chlamydia is the agent that commonly causes ‘eye colds’, dirty ceres and deeper infections of the respiratory tract including the airsacs. Although treating Chlamydia infections with fluoroquinolones may eliminate clinical signs, this group of medications is not as effective at actually clearing these organisms from the pigeons body as other antibiotics such as doxycycline. ‘Baytril’ has no action against fungi, viruses, canker or parasites.
The correct dose
The dose of ‘Baytril’ in birds is 10-30mg/kg given twice orally. The strength of ‘Baytril’ and all other oral syrup brands of enrofloxacin in Australia is 25mg/ml. This means the dose for a pigeon is 0.2-0.6ml of the nett syrup per bird twice daily or 5-15mls per litre of water. Years ago, lower doses were recommended but were found not to be effective against most infections.
Problems with using ‘Baytril’
Treating pigeons with ‘Baytril’, even healthy ones, for more than 4 days almost invariably causes a yeast infection (often called ‘thrush’). There are always low numbers of yeasts in the bowels of pigeons. Their numbers are kept in check by the normal ‘good’ bacteria in the bowel. ‘Baytril’ kills many of these. With nothing to keep them in check, the yeasts quickly multiply up leading to the development of green and sometimes watery droppings and potentially a loss of race form.
Treating young growing pigeons with ‘Baytril’ may permanently deform their joints. ‘Baytril’ can interfere with cartilage deposition on the surface of young growing joints leading to permanent deformity. This side effect is dose dependent and so young pigeons and in particular nestlings should only be treated with extreme caution and obviously only when necessary. When treated, they must be dosed accurately.
Treating hens that are about to lay with ‘Baytril’ has been associated with the embryos in those eggs subsequently dying.
Treating pigeons with fungal infections with ‘Baytril’ makes them worse.
Treating unwell pigeons with ‘Baytril’ in the absence of diagnostic work can waste time treating for the wrong problem while disease advances and can subsequently interfere with test results when testing is done.
Treating pigeons with ‘Baytril’ is not part of a routine pigeon health management program. At various times of the pigeon year, medication is used to prevent or control disease and prepare the birds for racing etc. ‘Baytril’ is not used in this way. It has no preventative property but simply kills organisms that are sensitive to it that are in the pigeon at the time of treatment. If birds are re-exposed to these organisms the day after the treatment stops they will be re-infected. I recently had a fancier tell me that every year as racing approaches he gives his race team ‘Baytril’ 1ml to 1 litre of drinking water for 10 days and that he considered this ‘essential’ for success. Using this drug in this way would achieve absolutely nothing apart from perhaps making the fancier feel better in some way. At the time of writing, it is about 8 weeks before racing starts in Victoria. I had another fancier ring me recently. He explained that he had given his race team, in preparation for racing, a long course of doxycycline, a long course of ‘Sulfa AVS’ (another antibiotic blend). The purpose of his phone call was to ask if he should now give a long course of ‘Baytril’. I found this call rather disappointing, for years well publicised pre-race programs have been published by vets. If nothing else, it just showed how some fanciers have an unreasonable over reliance on antibiotics. Despite giving all these antibiotics, the fancier had not treated his birds for the common parasitic diseases, had had no testing done on his birds to see in fact if any medications were necessary and it had apparently not occurred to him to contact an avian vet earlier for advice.
When to use ‘Baytril’
The first thing to say is that ‘Baytril’ is a prescription medication that should only be used in the loft after talking to your veterinarian who should have supplied it to you in an appropriate way. It is worth noting that there are heavy penalties for veterinarians who supply such medication without ensuring its correct use. Appropriate supply does not mean examining another bird with an unrelated problem 6 months earlier. Department of Human Services officers do masquerade as pigeon fanciers and attempt to buy prescription medication from vets in order to ensure correct supply. One high profile veterinarian once wrote that fanciers should only ask a vet to supply such medication inappropriately if they are prepared to pay any fine he may incur and support him and his family until he is allowed to practice again.
Many pigeon fanciers just want medication, even if they are quite expensive, 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 an expensive drug. In Australia, a 100ml bottle costs about $80. At the average dose of 10ml/L and based on an average water intake of 45ml per pigeon per day it costs about $40 per day to treat 100 birds. A 5 day course therefore costs $200. To treat 300 birds would cost $600. I would want to check with a vet that a course of medication costing this much was really worthwhile and going to give my birds benefit before I just did it.
On a lighter note, most fanciers have long term relationships with their vets and it is important to that vet that any supply of medication is used appropriately by the fancier. It is common sense and logical really but “Baytril’ is usually used when an infection sensitive to it is diagnosed and particularly if other cheaper antibiotic alternatives are thought likely to be less effective. Usually if individual birds are infected they are separated and treated individually with the nett syrup given to the mouth. If there is evidence of spreading disease or more than 10% of a flock is infected then usually the flock is treated through the drinking water. It is worth repeating that ‘Baytril’ is not a good first line of treatment for respiratory infections caused by Chlamydia because although it tends to reduce symptoms ie make the birds look better, it is not as effective at actually clearing the organism as other antibiotics such as doxycycline and also causes ‘collateral damage’ killing a lot of the ‘good bacteria’. Also only approximately 15% of Streptococcal strains (a cause of bacterial infection in pigeons) are sensitive to ‘Baytril’ and so it is not a good choice for this type of infection.
‘Baytril’ is however 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 in particular 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 also to see if that antibiotic should be ‘Baytril’ or not.