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Dr Colin Walker established the Australian
Pigeon Company in 1994, to develop, manufacture and distribute a
range of veterinary medicines and health supplements for pigeons.
Dr Walker's veterinary expertise, together with his knowledge of
the requirements of pigeon racers, gathered through experience of
his own race team, place him in the unique situation to develop
such products. The result is a range of quality products made for
the pigeon racer and based on sound veterinary knowledge.
Nature of the disease The disease canker is caused by a protozoan Trichomonas columbae. This is a microscopic single-celled organism. It lives within the digestive tract of pigeons, in particular the throat and crop, and can also involve associated areas such as the bile duct. The organism is fragile in the environment, only surviving for a few minutes once outside the bird. This helps with control of the disease and means that the birds cannot become infected from the loft or immediate environment as happens with other diseases such as worms and paratyphoid. The organism (trichomonad) requires intimate contact between birds to be spread and is usually transmitted by saliva or pigeon milk. Saliva contaminates food and water. As a pigeon drinks, the organism swims away from its beak and, when another pigeon comes to drink, it not only drinks the water but also the trichomonads there. When a pigeon sorts through grain, each dropped grain contains a small amount of saliva. In this way, the disease can also be spread through a feed hopper. Adult birds 'billing' can transmit the organism, as do parents when feeding their nestlings. Control of canker during the breeding season Correct medication is vital during the breeding season so that the level of natural immunity in the weaned youngster is as high as possible. Because the severity of the disease varies in different lofts, there is no single blanket program that is best for all lofts. There is no drug that by itself will cure canker in a loft. It is a matter of using medication correctly so that the birds can establish a strong natural immunity to the disease. It is this natural immunity that, in the longer term, protects them from the disease. What causes canker to appear during the breeding season? In health, every time the feeding stock bird feeds its youngsters, it passes on some of its own trichomonads to them. This gives the youngsters a controlled gradual exposure to the organism, which in turn allows them to establish their own natural immunity. Clinical disease appears in the babies when the stock birds shed too many trichomonads over a given period of time to their youngsters. Increased rates of trichomonad shedding will occur if: • the stock birds are stressed for any reason - Anything that stresses the stock bird will lead to an increased rate of trichomonad shedding and includes such things as a poorly designed loft, poor management practices, incorrect feeding, and other concurrent diseases. • the stock birds' natural immunity is not high - Stock birds are likely to shed higher numbers more readily when breeding if their own natural immunity to the strains present in the loft is not as yet solid. This can occur if new stock birds carrying different trichomonad strains have been introduced to the loft during the non-breeding time. All birds carry some immunity to the resident trichomonad strains in their loft. When birds from different lofts mix, they exchange their trichomonad strains. Adult stock birds during the non-breeding season are not stressed and so exposure to any new strains brought in by introduced birds is unlikely to lead to disease. They are not moulting, not breeding, and have plenty to eat, and therefore no sign of canker occurs. However, when paired, if their natural immunity to the new different strains is not solid, the stress of feeding will cause them to 'break down' and shed larger numbers of trichomonads. In the same way, the introduced birds need to establish an immunity to their new loft's resident strains. This is why canker is more of a problem in lofts that are still establishing with birds coming from a variety of other lofts. As the years roll by, fewer new birds are introduced and so the chance of new trichomonad strains getting into the loft decreases. The birds' immunity to resident strains becomes solid and the effect of the disease is less marked. Many fanciers are frustrated when canker appears in the stock loft. With excellent care in a good loft, they wonder just how it is that the disease can come. Certainly they are on the right track with this approach because in a good loft under good care it is less likely that the stock birds will shed large numbers of trichomonads. However, some strains are so active that problems will arise no matter how well the birds are cared for. How to manage an outbreak of canker during the breeding season When canker does appear during breeding, its management is two-fold. It is a matter of: 1. treating the sick youngsters - In lofts with a canker problem, all youngsters should be checked daily. If a sick youngster is noticed it can be successfully treated, and such youngsters can go on to become champions. Either Spartrix or Flagyl tablets* can be used, however, Spartrix is more convenient to medicate the nestlings. The dose of Spartrix is one tablet per adult bird. Estimate how big the youngster is compared to the adult and give it this proportion of the tablet once daily until well. Usually, one to four doses are required. It is often good to also medicate both the nest mate and parents for 2 days. If the unwell youngster is slow to respond, it is usually best eliminated. Individual pairs that breed youngsters with canker are best mated to different birds for subsequent rounds. At the same time, it is important to 2. decrease the number of fresh cases - This is done by checking the number of trichomonads that the stock birds are shedding. This is achieved by giving 2 days Turbosole* periodically. The exact frequency depends on the incidence of canker but usually every 1 - 3 weeks is appropriate. One needs to give sufficient 2-day courses to limit the number of new youngsters with the disease, but at the same time to avoid overuse of the drug so that the developing youngster is still getting an on-going exposure to the organism. It is a matter of working between these two extremes. The important thing to always remember with canker during the breeding season is that the disease can never be controlled through medication alone. It is the development of a strong natural immunity that protects the birds in the longer term. It is important that medication is used to keep the birds well but used in such a way as to not interfere with the development of this immunity. >>Back to Top Preventative programs for the breeding season In the stock loft that had canker last seasonTreat all stock birds for 5 - 7 days before pairing and then for 2 days every 1 - 3 weeks once paired. Frequency of treatment depends on the severity of the problem and the control achieved. Try and coincide these 2-day treatment periods with the time of hatching when trichomonad shedding is highest. If canker is still a problem in certain pairs, try to only medicate these pairs. This can be achieved by breeding from them in individual runs and only medicating their water with Turbosole for 2 days as required or alternatively leaving them in the loft and just treating them with Spartrix or Flagyl tablets for 2 days when needed. Splitting the pair and remating each to other birds for the next round may help. Stock birds can be crop flushed before pairing to identify those birds carrying large numbers of trichomonads. These birds are not only more likely to shed large numbers of trichomonads more readily once paired but also to pass on their genetic susceptibility to canker. In the longer term, it is best if these birds, when identified, are eliminated. The problem is that they may, in fact, be the winners and here lies the challenge for the fancier - to breed birds less susceptible to the disease that are also winners. In the stock loft that had no canker last season No treatment is required. If there was no problem with canker in last year's nestlings, then it is best not to medicate for canker. Any medication will stop the paired bird shedding trichomonads and therefore interrupt the on-going exposure of the growing youngster to the organism. This leads to a lower natural immunity and may in fact create a vulnerability to the disease in the postweaning period. In the stock loft that had no canker last season but to which new stock birds have been introduced As discussed earlier, all birds carry in their systems the resident trichomonad strains of the loft and usually have a strong natural immunity to them. A newly introduced stock bird brings these strains with it. These strains may not have been encountered by your own birds and the new birds may not have encountered yours. Both lots of birds in time must, through exposure, become immune to the other strains. If introduced in the non-breeding time, when the stock birds are not under any stress, i.e. not moulting and in a good loft with plenty to eat, no clinical disease will be seen. However, with the stress of breeding, any immunity already developed will be put to the test. If immunity is not solid at the time of breeding, excessive trichomonads will be shed and the youngsters may develop canker. For this reason, new birds, especially if introduced immediately before pairing, should ideally be mated in individual runs and the youngsters monitored. If youngsters in the main loft begin appearing with canker, the loft should be managed as discussed under the section How to Manage an Outbreak of Canker During the Breeding Season. Control at weaning In lofts with a canker problem, all youngsters can be treated with Turbosole for 2 - 3 days at weaning, to avoid any check in their development through this stressful time. In the longer term, however, the important thing during this time is that only youngsters with the disease should be treated so as not to interfere with the developing natural immunity of the flock as a whole. Affected birds should be separated and treated with either one-quarter of a Flagyl tablet (200 mg) or one whole Spartrix tablet once daily until well. This usually takes 1 - 3 days. Alternatively, the unwell youngsters' water can be medicated with Turbosole (1/2 teaspoon to 1 litre of water). It is important, however, to ensure that any unwell youngster is still able to drink. Turbosole can also be mixed into a paste and the youngster's throat painted with this using a cotton bud. The group of youngsters, as a whole, should only be treated if more than 10% of youngsters are showing signs, usually with Turbosole for 2 - 3 days. However, in this situation it is best to seek veterinary advice. Control during the race season If canker was a problem during the breeding season, this tells us that the birds have the potential to have trichomonad flare-ups in response to stress and that canker is likely to be a problem during racing. However, through good management and the correct use of medication, it is hoped, however, that most birds have developed a reasonably strong natural immunity by the start of the race season. The stress of racing will put any immunity that the birds have formed to the test. Depending on what stresses the birds are under, trichomonad levels will rise and fall. When high, they have a typical parasitic effect, weakening the bird, in the process creating a vulnerability to secondary infection (particularly respiratory infection) and compromising race performance. They also produce a toxin that makes the birds feel unwell. Birds with elevated trichomonad levels are said to have 'wet canker'. Signs of infection can be subtle and quite varied. Typical signs that would alert the fancier to its possible presence include: 1. 'Penguin' posture - Associated with proventricular (glandular stomach) and crop pain. Birds will lean back on their tails and gulp. Noticed particularly after eating and drinking. 2. 'Dry feather' - Due to lack of down feather drop and bloom production. 3. 'Leady' feel - Affected birds will not come into condition and feel heavy in the hand. 4. Wet dropping - Inflammation in the digestive tract creates a thirst, leading to elevated water intake and urine production. This produces a clear watery rim around the dropping. 5. Green droppings - Due to digestive tract irritation and in some birds decreased food intake. 6. Inflammation in the throat - Tonsillitis and increased clear to grey bubbly mucus. 7. Interference with crop function - Delayed crop emptying and sometimes vomiting. 8. Increased food consumption by team as a whole 9. Dry yellow canker - In birds of any age, this tells you that many other birds have elevated trichomonad levels, which have not yet passed the threshold for yellow material to form. 10. Indirect signs - Poor loft flying, poor tossing, respiratory problems that respond poorly to medication or quickly relapse, a dramatic improvement in the birds' general vigour in response to anticanker medication are all suggestive. Definitive diagnosis, however, depends on microscopic examination of a crop flush. Microscopic changes that are suggestive of the problem also develop in the dropping,. These changes are associated with the stress of the disease and include elevated E. coli and yeast levels. These changes, however, do not occur in all birds. Race lofts are divided into one of two groups for the purposes of canker management: 1. Those without resident wet canker strains. Since the rapid spread of wet canker strains through the racing pigeon fraternity since the early 1990's, not many lofts now fit into this category. In these lofts, canker is unlikely to be a problem during breeding and crop flushes done on members of the race team will be repeatedly negative. Here, an effort is made to prevent the introduction of these strains with returning race birds. In races where the birds are provided with drinkers, returning race birds are medicated with Turbosole (1/2 teaspoon to 1 litre of water) for 24 hours upon return. Often the single big drink that returning race birds have, although not sufficient to treat an active infection, will clear the trichomonads picked up from a recent exposure. 2. Those lofts with resident wet canker strains. In these lofts, canker is likely, but not always, to be a problem during breeding, and crop flushes done on individual race birds, particularly following stress, will contain large numbers of trichomonads. Here, attention focuses not on treating returning birds, because the strains are already in the loft, but on keeping the numbers of trichomonads low so that they cannot affect race form. This is achieved by giving periodic 2-day courses of Turbosole. The length and frequency of each treatment is variable from one loft to the next, being affected by a number of factors intrinsic to that loft. In most lofts, however, 1 - 2 days every 1 - 3 weeks will keep trichomonad levels low. In the absence of testing, treatment 2 days every third week is advised. This is usually given on the Monday and Tuesday. Preferably, however, the use of Turbosole within a loft is based on the results of testing birds from that loft. If trichomonads are detected in a crop flush, an initial 2-day course of Turbosole is given. Follow-up crop flushes are then done every few days so that the exact time that trichomonads start to reappear is detected. Once this interval is known for that loft, then, given a constant set of loft parameters, the trichomonads will repeatedly and predictably reappear at this time. Follow-up 2-day Turbosole treatments at this interval will ensure the trichomonad levels are always low and therefore not given a chance to affect race form. The main loft parameters are the genetic make-up of the birds, the strain(s) of trichomonad present, the loft environment and the management practices. If these change, the use of Turbosole may also need to change, e.g. increased tossing combined with cold weather may stress birds, leading to premature trichomonad flare-ups and a shortening of the treatment interval for one or two treatments. Generally, however, as the season progresses, the need for medication declines as the birds get older, both their level of fitness and natural immunity rise and, in particular, in Victoria, as the weather becomes warmer. Other sites of canker As fanciers would be aware, most canker lesions are found in the bird's throat and are often associated with their tonsils here. However, canker can affect a variety of other sites. Navel canker If pigeon milk is spilt into the nest bowl and this, in turn, contaminates a nestling's navel that has not fully healed, a canker nodule can develop on the navel. Treat the nestling with the correct dose of Spartrix daily (usually 1 - 4 days). Antiseptics (such as Betadine) can be applied to the navel daily until the area has dried. After several days, the nodule can be 'popped' like a scab and separated from underlying healthy tissue. The condition must be caught early for treatment to be successful and for the youngster to be of value racing. The condition is more likely to occur when nest conditions are poor, leading to delayed navel healing, and is therefore often associated with 'wet nests' and with inappropriate nesting material. The condition is also more likely to occur if the parents are shedding large numbers of trichomonads. A suggested course of treatment is: • Treat youngster and both parents daily with Spartrix • Dab navel daily with Betadine • Clean nest • Treat parents for 'wet nest' if appropriate (PVM Powder and Probac) • Improve nest conditions Sour crop In pigeons with sour crop, at least 90% have an internal canker nodule located at the base of the crop or within the glandular stomach (proventriculus). As the nodule increases in size, it squashes the windpipe making breathing difficult and blocking the crop outlet. This interferes with crop emptying, leading to bacterial infection of the crop and secondary starvation and dehydration due to the crop contents not being able to pass into the bird's system. Usually by the time the bird is noticed to be unwell, the condition has passed the point where it will respond to treatment. Deaths often occur due to the nodule growing through the stomach wall, leading to stomach contents leaking into the chest. Alternatively, the nodule can damage the heart or large blood vessels within the chest, causing sudden and severe bleeding. Such birds are often found dead on the floor with blood coming from the mouth. It is always worth attempting to treat valuable birds and I suggest : • Manually empty the crop • Give electrolytes in water • Treat bird with 3 drops Baytril twice daily • Treat bird with 1 tablet of Spartrix or a 1/4 Flagyl tablet or 0.5 ml Flagyl syrup once daily • Separate unwell bird from loft mates Cloacal canker The cloaca is the pigeon's bottom. Within its wall is a gland called the Bursa of Fabricius. This gland is an important part of the youngster's immune system. It shrivels up and disappears during puberty. If pigeon milk containing trichomonads contaminates the nest bowl, the trichomonads can cause a trichomonad nodule to develop in the cloaca. Affected birds are usually noticed to be a bit quiet or their growth is slightly retarded compared to others of their age. On examination of the cloaca, a firm lump can be felt in the skin above it. Sometimes these lumps do not become apparent until the postweaning period. Affected birds should be treated daily with either Spartrix or Flagyl, usually for 3 - 4 days, by which time the nodule has usually localized and can be expressed by gentle but firm pressure through the cloaca. Canker nodule in throat or crop Older youngsters or mature stock birds with a reasonably strong natural immunity will often try and localize a canker infection, leading to nodule formation. If in the throat, these nodules can usually be seen or if in the crop wall can usually be felt as firm mobile lumps ranging in size from 0.5 cm to 4 cm in diameter. Affected birds are treated daily with Spartrix or Flagyl tablets. Once localized (usually 1 - 4 days), throat lesions can usually be teased free with a cotton bud or crop lesions pinched free into the crop. Occasionally, surgical removal is necessary. Premature attempts at removal usually result in excessive bleeding. Internal canker Canker can infect internal sites associated with the digestive tract, notably the bile duct, which drains bile from the liver into the bowel. Birds with internal canker nodules usually display non-specific signs of illness, including weight loss, lethargy, reluctance to eat and green diarrhoea. The final diagnosis is often made at autopsy. In lofts with a canker problem, it is usually best to include a daily Spartrix or Flagyl tablet in the treatment regime of an unwell bird in case this is the problem. Sinus canker Sometimes canker organisms can invade the sinuses through the slot in the roof of the mouth and form a canker nodule here. The birds present with a firm swelling across the forehead between the base of the cere and the eyes. Anticanker medication is given for 4 - 5 days to kill the active infection. After this, lancing the area by making an incision in the skin over the most prominent area of the nodule enables the canker nodule to be expressed. Once the nodule is removed, it is best to continue with anticanker medication for several days. Healing is usually uneventful. Other sites It is important not to confuse infection in other parts of the body with canker. Trichomonads, partially because of their fragility, can only infect the digestive tract and associated structures. Pigeons are very restricted in their response to infection. Their white blood cells lack many of the enzymes (called lysosomes) that are normally found in mammals and therefore cannot produce pus. For this reason, no matter where the site of infection, the resultant reaction often looks like a canker infection. Bacterial (or other) infections of the skin, feet and eye, etc. for this reason are often confused with canker because of their appearance. Medications Available Any one of a group of medications called nitro imidazoles are effective against trichomonads. There are four commonly in use: 1. Dimetradazole - The common brand name here is Emtryl, available as a water-soluble powder. Dimetradazole was the first nitro imidazole available and is still an effective drug, although trichomonad resistance to it in some areas is a problem because it has been used for the longest. It must be used with care as it has a narrow safety margin. Overdose leads to a reversible loss of balance and coordination and, in high doses, death. The medication can interfere with sperm production in cocks, leading to a temporary infertility, and so is not recommended for use during breeding. The usual dose is 1 teaspoon (3 grams) to 4½ - 8 litres of water. Lower dose rates should be used in stock birds feeding youngsters and during hot weather when water intake increases and evaporation occurs from drinkers, increasing the concentration of the medication. 2. Carnadazole - The common brand name here is Spartrix. It is only available in tablet form. It has a wide safety margin and is very useful for individual bird dosing, particularly youngsters in the nest. The dose is one 10-mg tablet daily. 3. Metronidazole - The common brand name is Flagyl. This is available as a water-soluble syrup and as tablets in a variety of strengths. It is very economical, with the tablets being useful to dose individual birds. Individual birds are given ¼ of a 200-mg Flagyl tablet once daily. Flagyl syrup is water soluble and is given at the dose of 5 - 10 ml per litre but is very sugary and not very palatable to the birds. 4. Ronidazole - This is available as a water-soluble powder under a number of brand names world-wide, including Ridsol-S, Turbosole, Tricho-Plus and Ronivet. The usual strength used is 10%. The dose at this strength is ½ teaspoon per litre. Weaker preparations are available but the birds need to be treated longer with these. The drug is very bitter so preparations stronger than 10% tend to be unpalatable to the birds. It has a very wide safety margin and is safe to use during breeding, racing and moulting. World-wide, ronidazole is the current medication of choice to treat canker. However, in some countries it is not available for use in pigeons, authorities being concerned that resistant organisms may develop. As the drug is used in food-producing animals such as pigs, its use is reserved for these. In any canker-control program, it is often best to rotate between at least two of these medications in order to decrease the chance of a resistant trichomonad strain developing. Currently, ronidazole-based preparations are used as the primary treatment because of their effectiveness and wide safety margin, but it is a good idea to swap to one of the other available drugs every third or fourth treatment. >>Back to Top THE PARASITIC DISEASES There are many parasites that infect pigeons
and I feel that it is beyond the scope of this book to discuss all
of them in detail. The most important and most commonly encountered
parasites are roundworm, hairworm, tapeworm, the external parasites,
lice and mites and Coccidia. RESPIRATORY INFECTION If you ask any experienced flier what health problem he fears the most, then if it is the breeding season he will probably say canker, but if it is the race season he will probably say respiratory infection. Respiratory diseases are very common in pigeons. They are the major cause of poor performance and pigeon loss during the race season. Young birds under stress are most at risk of contracting respiratory diseases, although healthy old birds can fall ill when exposed to respiratory diseases in the race basket. Race birds with respiratory infection can be difficult to detect and yet, like a human athlete with flu, cannot compete. When some fanciers talk about respiratory infection, they give the impression that they are discussing a single problem and, yet, several organisms can be involved and often simultaneously. Clinical respiratory infection in pigeons is the end result of the interplay of a number of factors but, in particular, the type of infective organism and the vulnerability of the birds to infection are important . The respiratory system can be infected by Chlamydia, Mycoplasma, bacteria (in particular E. coli), fungi, viruses and mites. The control of some of these starts, in certain lofts, not only before racing and not even during breeding, but right before the stock birds are paired.Stress is always a big factor. The vulnerability of the pigeon is affected by what stress it is under. Stress weakens the bird, enabling infective organisms to cause clinical disease. The control of respiratory disease is therefore two-pronged. 1. Control of any predisposing stress factors - These can take the form of : (a) Environmental triggers, e.g. dampness, overcrowding, low hygiene (b) Management triggers, e.g. poor feeding, excessive tossing, or (c) Concurrent disease, in particular parasitism. This includes wet canker. The combination of either worms or elevated trichomonad levels and respiratory disease is very common. The fancier must establish a healthy loft environment, otherwise respiratory disease will continually recur, despite medication. 2. Correct use of appropriate drugs to either eradicate or keep the organism level low so that disease does not occur. The organisms that infect the respiratory system and how they are controlled are set out below. >>Back to Top Chlamydia Chlamydia is a microorganism that is found within the system of many pigeons all the time. There are many strains, which vary tremendously in their capacity to cause disease. Lofts tend to have resident strains to which those birds, often through their on-going exposure, have developed an immunity. In such lofts, it is only when the birds are stressed that the Chlamydia is able to flare up and cause disease. It is through contact with other birds (strays, in race units, new introductions) that new and potentially nastier strains gain entry to the loft. Control of Chlamydia is, therefore, double-barrelled and involves the control of stress to avoid resident Chlamydia strains flaring up together with the correct use of medication and the prevention of new chlamydial strains entering the loft. Control of stress to avoid chlamydial strains, already in the loft, flaring up A subsequent chapter deals with what constitutes stress and how to avoid it, but essentially this involves on-going good care with good management practices, a good loft environment and control of other diseases, notably the parasitic diseases. Any problem that weakens the birds makes them vulnerable to a chlamydial flare-up. Sometimes, however, despite the best possible care, because the strain of Chlamydia in the loft is virulent or the family of pigeons is particularly vulnerable (as with some European strains), it becomes necessary to medicate the birds through stressful times to prevent chlamydial flare-ups and the resultant clinical disease. The particular times when these flare-ups are more likely to occur are during breeding, after weaning and during the racing season. Breeding Stress for a stock bird is breeding. Stressed stock birds will shed the organisms in their droppings, saliva and eggs. If the Chlamydia is in the egg, the developing embryo is weakened and can either die during incubation, during the hatching process or as a nestling or, if it survives, be a retarded youngster. In a nestbox heavily contaminated with Chlamydia, the developing youngsters become weakened and die. If these things have happened in earlier years, and breeding has commenced, it is too late to treat the stock birds. However, medication (usually doxycycline) can be given before mating to decrease the level of Chlamydia in the stock birds' system. This means that they will then require more stress before they start to shed the organism. The length of treatment depends on the need, usually 7 - 30 days. If your loft has a history of chlamydial problems during breeding, a prebreeding doxycycline course is a good idea. Chlamydia can be completely cleared with a 30 - 45-day course of doxycycline. However, this is rarely done because the weaned youngsters will be exposed to the organism later in life and may in fact be more vulnerable to illness through this lack of exposure and the resultant low level of natural immunity. Doxycycline, like other antibiotics, causes disruption of the normal bowel bacteria, interfering with vitamin metabolism and calcium absorption. It is therefore important that preventative courses are completed several weeks before pairing and there is benefit in giving the birds probiotics, vitamins and calcium supplements following them. After Weaning The next vulnerable time is the postweaning period, when both weaning and moulting are the underlying stresses. In Victoria, Australia, January to May are the respiratory months. Most lofts contain large numbers of young birds having just had the stress of weaning and now having the stress of moulting, coupled with young bird tossing and racing. It is a time of high humidity and fluctuating temperature, conditions that favour respiratory disease. Between 1 December and 1 March (the usual time that the last youngsters are weaned in many lofts in Australia), fanciers must monitor the youngsters, in particular, for signs of 'one-eye cold', dirty wattles or sneezing. However, green watery droppings, failure to thrive, shortness of breath and a reluctance to fly may also be indicative of the problem. Because of the disruption to normal bowel bacteria caused by the antibiotics, which can compromise feather quality and check development, and also because of the interference with development of a natural immunity, it is important that only the birds that need medication should receive it. If only a small number are affected, they may be treated individually with doxycycline (Vibravet 50 mg, 1/2 tablet once daily) or Baytril (3 drops twice daily). Once on medication, they stop shedding the organism and so there is no need to isolate them. If one bird has become unwell while the others are okay, it is often a reflection on its vigour. If such a bird fails to respond quickly or relapses, it is unlikely to go on and make a competitive race bird and is often best eliminated. If more than 5 - 10% of young birds are affected, with fresh cases daily, then all should be treated. Usually doxycycline 12% (½ teaspoon per litre for 3 - 5 days) is used. However, such a situation represents a major flaw in the birds' environment or management and the longer-term solution is not going to be drugs but identification and correction of the underlying cause. In young birds, this is often overcrowding. A faecal examination and a crop flush are a good idea to check for any concurrent disease in addition to reviewing other loft factors. After 1 March in Australia, as the youngsters get older, fanciers look for signs of poor loft flying, excessive panting after training, and sneezing within the loft. Even in the most healthy lofts, there can be occasional outbreaks of respiratory diseases. It is important to recognize that more than three sneezes within 5 minutes is a significant indicator of early respiratory disease. One would expect two to three sneezing outbreaks between January and May, even in the best managed loft. If there is doubt as to whether a sneezing outbreak is due to chlamydial respiratory infection, a test called a chlamydial antigen test can be done on the droppings by an avian veterinarian. Medication is used during this time as it is from 1 December to 1 March. However, provided the birds are well, medication is best avoided. With on-going good care, the birds are likely to fix themselves and the level of natural immunity they form as a result will be much higher. >>Back to Top During The Racing Season Exposure to new strains of respiratory infection All lofts are continually being exposed to respiratory infection through the race unit. In the race unit, many different birds from many different lofts mix intimately in a warm humid environment, which is ideal for the transfer of disease. In addition, the confinement, different feeding patterns and time away from the loft stress the birds. As a result, the Chlamydia levels can rise to the point where form is affected. If respiratory symptoms are noted, all birds are treated with antibiotics (eg Doxy-T, Resfite) for 3 - 5 days. It is important to treat these outbreaks early before they change into the serious form of respiratory, which can involve, and permanently damage, the air sacs, thus seriously compromising race performance. Stress-induced flare-ups of resident strains As mature race birds, it is racing itself that provides the stress, testing the level of immunity formed by the birds. In a well managed loft where drugs have been used correctly, this immunity should be relatively solid by the start of the season. Racing puts this immunity to the test. In race birds, signs of Chlamydia flare-ups are considerably more subtle. The birds are older, their natural immunity is higher and their response to disease is different. The signs observed have been modified by these factors. Birds with respiratory infection have lost their zest for life and this is reflected in their race results. However, many things can lead to disappointing results and, as antibiotics have the potential to make a race team worse, I, like most fanciers, have to be convinced that respiratory infection is present and that their use is warranted. Birds that are reluctant to fly, quiet in the loft and with dry feathers (no bloom) are suggestive of respiratory infection. Sneezing (more than three times in 5 minutes from 100 birds), scratching at the nose, yawning, and wiping the nose on the wing butt all indicate irritation of the upper airways. On opening the beak, the tonsils may be inflamed, a thick white mucus may be extending into the throat from the windpipe or from the slit in the roof of the mouth, which may be closed due to swollen edges, the top of the windpipe may be red and inflamed, the beak at the nostril opening may be wet, the cere may be slightly discoloured or there may be a slightly mucous component to the birds' grunt while the gums or the muscles may be bluish. Chronically infected birds show delayed recovery after a race and will develop green droppings after stress because of damage to the liver. Testing of the droppings usually confirms the diagnosis. If the loft has not had respiratory problems in previous years, I feel it is best to try and avoid antibiotic medication but monitor the birds closely and treat for 3 - 4 days if respiratory infection occurs. If respiratory infection during racing has been a problem in earlier years, preventative courses of antibiotics can be given before racing in the same way that they are given to stock birds to decrease the level of Chlamydia in the birds' system so that they are less likely to break down with the stress of racing ahead. Depending on the severity of the problem in earlier years, these courses are usually 7 - 20 days in length. In such lofts, follow-up periods of medication may be necessary during the season, and a common recommendation is 3 days treatment every third week, with Monday, Tuesday and Wednesday usually being the days to treat such a resident problem. After antibiotic use during racing, the birds should always be given a day on either probiotics or multivitamins. Prevention of new chlamydial strains entering the loft New strains enter the loft through exposure to other birds. Stray youngsters and youngsters bought at squeaker sales are always high risk because, due to their age and the stress they are under, they are likely to be shedding chlamydial organisms they are carrying. Strays should be removed immediately and birds introduced deliberately only from reliable sources. By far the main means of exposure is through the race unit. One stray is one exposure. Ten birds going to a race and each sharing a drinker with ten other birds is 100 exposures (i.e. like getting 100 strays in one day). In some situations and, in particular within certain clubs and areas of Australia, it becomes necessary to medicate returning race birds to guard against infection picked up in the race unit. Management It can be seen that the appropriate management regime for Chlamydia , including use of medications, varies from loft to loft depending on each loft's earlier problems and particular loft-based factors. An example is what I do with my own birds. My own loft is based on an established Australian long-distance strain. Chlamydia is not a big problem. I do not medicate my stock birds before pairing because I do not have chlamydial problems during breeding. If I did, however, I would treat for 7 - 21 days before mating as the need dictated. I get three to four youngsters per year with eye colds and these are individually treated with Baytril (3 drops twice daily). To date, these have responded promptly. My race loft is very enclosed, which gives me good control over the loft environment and enables me keep it as close to ideal as possible. Draughts, temperature extremes and high humidity can be avoided. I would like to think that I care for my birds well. Under my system of management during racing and with my loft environment, the resident chlamydial strains do not flare up during the race season and so I do not treat preventively before racing. I do, however, have intermittent flare-ups of wet canker and the birds are regularly checked and treated through racing for this. I feel that with inadequate control of this, because of the trichomonads parasitic, i.e. weakening, effect, it is likely that the Chlamydia would also become a problem. I check my birds droppings once or twice weekly and the birds are monitored closely for signs of respiratory infection. If a respiratory infection became established, the birds would be given a 3 - 5-day antibiotic course. My returning race birds are not treated for respiratory infection because, to date, this has not been a problem. However, if it was a problem, I would treat them. >>Back to Top MYCOPLASMA Mycoplasma is a problem of the race season. It is what is called a primary erosive disease. Many vets agree that Mycoplasma by themselves do not cause disease and, in fact, in experiments in which healthy pigeons have been deliberately infected, the birds have not become sick. However, the organisms do superficial injury to the lining of the respiratory system, enabling secondary organisms, notably Chlamydia, bacteria (such as E. coli) and fungi (such as Aspergillus), to become established. In this way, Mycoplasma, although not directly affecting health, has a big effect on race performance. Failure to control the problem in an affected team renders all attempts at success hopeless. Some Dutch vets state that as many as 90% of teams are affected and teams are presumed to be affected unless they have been recently treated. Pigeons harbouring Mycoplasma organisms cannot achieve superhealth and are prevented from achieving top racing results. Mycoplasma are primary pathogens of the respiratory system and the signs displayed by the birds depend on the part of the respiratory system affected. In the throat, nose and windpipe, signs are similar to those described for Chlamydia earlier. However, Mycoplasma notably causes inflammatory changes in the top 20 - 30% of the windpipe, causing mucus to accumulate there and birds that have a broken grunt or sound mucousy in the upper airway always make me think of Mycoplasma. Where the airsacs are affected, the birds cannot properly breathe and so even moderate exercise is tiring and sometimes forces the birds to land on the nearest available surface, which may be a tree or building near the loft. Because of the difficulty in breathing, the gums and muscles can turn blue and because of the inability to exercise, muscle tone and race fitness cannot come. The airsacs regulate fluid within the body by controlling evaporation of moisture from their surfaces. When diseased, excessive moisture is lost and the birds, therefore, need to drink more even after moderate exercise, or run the risk of dehydration. Often, however, signs are very subtle and may simply be deteriorating performances. Like Chlamydia, Mycoplasma are more likely to cause disease when the birds are stressed. Most lofts do have resident Mycoplasma strains and new Mycoplasma strains can enter the loft through contact with other birds. Mycoplasma is a difficult disease to diagnose in the live bird. Only certain labs culture Mycoplasma, which is an expensive procedure. Blood tests are used to diagnose the condition in chickens. There are changes at autopsy, both grossly and microscopically, that are suggestive. Changes are also found on faecal smears and crop flushes of affected birds, which are discussed in other sections of this book. A good response to a short treatment trial with Doxy-T (see Medication Guide) also supports the diagnosis Management What should the fancier do if the problem is diagnosed? • A health profile, i.e. examination of the saliva and droppings, to assess any concurrent disease that may need treatment and general on-going good care to ensure a good response to medication. • A gradual return to exercise. Always with respiratory infection there is an extended convalescence of usually 1 - 3 weeks. The birds must be given time to recover their fitness once medication has cleared the infection. They should not be forced to fly around the loft and once it is apparent that their vigour for flying has returned, initially short tosses only should be given (less than 1/2 hour). Observe the birds closely for signs of breathlessness on landing from these tosses and only when they are handling these well should longer tosses be given. When managing tosses of 1 - 1 1/2 hours well, it is usually safe to resume racing. In well-managed lofts with no other health problems, response to treatment can, however, be dramatic and I have had an interesting experience where two flyers both diagnosed with Mycoplasma in their teams succeeded in gaining 1st and 2nd Federation (3000 birds) in an all-day 500-mile race 3 weeks after treatment. • Good food, good care and an appropriate multivitamin supplement speed recovery. • Medication. The choice of drug is sometimes dependent on the involvement of secondary organisms such as Chlamydia and E. coli. Baytril can be used with care during racing. Other antibiotics such as doxycyline, Tiamulin or Tylan are effective. However, the current recommendation is that doxycycline and Tylan combined be given. An initial course of usually 5 - 10 days is given depending on the severity of the infection with several follow-up courses, usually 2 - 3 days every 2 - 3 weeks until one is sure that the birds are well. The usual preparation used in Australia is Doxy-T which contains doxycycline and Tylan. In some Federations in Australia, there is significant risk of picking up nasty Mycoplasma strains in the race basket. In these areas and Federations, antibiotic combination medication is given throughout the season to control the problem, usually for 2 - 3 days every 2 - 3 weeks depending on the severity of the problem and the control achieved. >>Back to Top |