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Pigeons
EXOTIC PET MEDICINE II
0195-5616/94 $0.00 + .20
PIGEONS Roger W. Harlin, DVM
The association of humans with pigeons and doves dates back to as early as 3000 to 5000 B.C. Other birds were bred for meat and egg production, but pigeons are thought to have been kept to aid agriculture. Their ability to fly long distances, select the richest nutrients, and then return to the same nesting place made their droppings an easily collectible source of rich fertilizer for growing crops in arid climates and on infertile land. As time went on, humans found more uses for pigeons. Best known is the part they played in communication during wartime before the invention of the wireless. Throughout history, the more advanced the civilization, the closer the association of humans with pigeons and doves. Pigeons are classified as flying and performance, fancy, or utility pigeons. There are standards of perfection for exhibition of almost 300 breeds of fancy pigeons. All breeds are derived from the common rock dove (Columba livia). Most of the pigeons kept are Racing Homers, trained to compete in the sport of racing. Other breeds, such as Tipplers, High Flyers, Rollers, Nose Divers, and Doneks, are bred for their aerial acrobatic abilities. Pigeon meat, or squab, is still considered a delicacy in many parts of the world. Some utility breeds are capable of producing 12 to 16 pounds of meat yearly. In contrast, other breeds produce four to six young per year. PHYSIOLOGY AND REPRODUCTION
Although pigeons usually mate for life, most birds will readily take a new mate after a short period of separation. A system of polygamous From Southside Dog, Cat, and Bird Hospital, Oklahoma City, Oklahoma
VETERINARY CLINICS OF NORTH AMERICA: SMALL ANIMAL PRACTICE VOLUME 24 • NUMBER 1 • JANUARY 1994
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breeding called the "bull system" is often used to breed numerous hens to a prepotent cock. Eggs are fostered to feeder 'pairs. This system may yield two babies from the favored cock every 2 to 3 weeks, whereas natural pair methods will yield two youngsters at most every 6 to 7 weeks. The breeding season is in the spring. Pigeons lay two eggs about 40 hours apart. Incubation is 17 to 19 days. The cock assists in incubation from late morning to mid-afternoon. Several days before the eggs hatch, "crop milk" formation is stimulated by prolactin secreted from the pituitary gland. An actual desquamation of the crop epithelium, crop milk is very rich in protein and fats and is all that squabs receive from the parents for the first week. During the second week, grains and other food are regurgitated by the parents, and the production of crop milk ceases. The cock plays a role equal to or greater than that of the hen in feeding the squabs, particularly if the hen has begun incubation of the next clutch before the squabs have been removed to a weaning pen. Weaning occurs naturally at about 4 weeks of age. Some fanciers believe that earlier weaning makes for a more resourceful older bird. Others prefer to leave the squabs in the nest longer, believing that extra help from the parents is beneficial. A pair typically produces two to three clutches per season. Pigeons reach maturity between 5 and 12 months of age, depending on breed and birth date. Toy breeds born early will mature faster than late-hatch giant breeds. Mature body weight ranges from 150 to 180 g in breeds such as the African Owl to over 1400 g in the American Giant Runt. Most Racing Homers weigh about 360 to 480 g. Pigeons have paired vestigial ceca and no gall bladder. The normal white blood cell count ranges from 8000 to 18,000 cells/mm3 and is generally 12,000 to 15,000/mm3 • The normal red blood cell count is 3 million to 4 million/mm3 • Total protein should be between 2 to 4 mg/dL. Body temperature is about 105° F.
HOUSING
Pigeon houses are called lofts. Pigeons do not require elaborate facilities; however, the birds will be more comfortable and productive if a loft is designed specifically for breeding, racing, or whatever the fancier is trying to accomplish. Lofts must be dry. Pigeons can tolerate extreme temperatures, but moisture and dampness will certainly result in illness and poor performance. Lofts must be well-ventilated but without direct drafts. Respiratory problems are seen in pigeons kept in tightly closed structures in which the air is stale and dust builds up. The ideal loft is built 1 to 2 feet above dry ground with wire floors. Ceiling vents provide good ventilation. A wire floor prevents direct contact with the droppings. Sand, cedar shavings, and many other litters ha~e been used s~cce~sfully. Some fanciers use a natural litter (dropping buildup), and their birds do well. The natural litter must be absolutely
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dry and should be used only in a closed flock. Generally, the cleaner the loft, the healthier the birds. However, there is evidence that a completely sterile loft is not optimum, because low-level contact of healthy birds to avirulent strains of coccidia helps to maintain immunity. Pigeons love to "own" property and raise families. It is this love of mate, loft, nest, and perch space that inspires them to excel as avian athletes. They will fly hundreds of miles under any conditions to be "home." Too many birds in too small a place will destroy their morale. Overcrowding is the worst enemy of pigeon health. The fancier must judge if certain pigeons are affecting the quality of life of others. Sometimes "troublemakers" may have to be removed from a particular pigeon society. Happy pigeons in clean, well-ventilated lofts are generally healthy pigeons that seldom require medication. NUTRITION
Proper nutrition is essential if pigeons are to maintain good form and resistance to disease. Nutritional requirements vary greatly according to season, moulting, growth, breeding, and the demands of performance or racing. Simple logic and common sense suggest that increased protein is important to growing squabs and is not as important to inactive birds in winter. More carbohydrates are beneficial in wintering birds in cold climates, because caloric needs will be increased. Higher fats and protein are helpful during the moult to enhance feather quality and growth. Racing demands a judicious feeding schedule. The requirements will vary with distance and race conditions. For instance, more fats may help a bird to fly 500 miles in headwinds, whereas more carbohydrates and being a bit hungry may enhance the performance of a 150-m* sprinter. There are a number of commercial pelleted rations and blends of grains. Following the instructions and recommendations of reputable companies is usually satisfactory. However, most fanciers have their own ideas and will make additions and corrections to commercial products. Austrian, maple, and Canadian peas are among the best protein seeds. Safflower seeds and Spanish peanuts are often used to supplement fats before races. Barley, wheat, and corn are good carbohydrate grains for winter. These grains are usually included in mixtures in varying amounts along with milo, kaffir, millet, oat groats, and many others. Grit can be offered, although it is probably not necessary. Many minerals are available in the balanced pelleted rations. An unsupplemented breeder diet of only grains, without calcium, vitamins, and trace minerals, will most likely result in defective squabs. PREVENTIVE MEDICINE
Medications will rarely be necessary if these guidelines are followed by the pigeon fancier.
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1. Buy quality stock from a quality breeder. Do not introduce new
birds into_an existing healthy flock until they have been quarantined and physically examined. The optimum length of quarantine is the time for a pair to raise two or three sets of babies. When quarantine is over, introduce one pair at a time to the existing flock. Allow each pair to establish territory before adding the next pair. This method minimizes the stress of pairs finding a place in the loft. 2. Examine all new birds for ectoparasites such as lice, mites, and pigeon flies. Perform fecal flotation and direct smears to check for helminths and coccidia. Examine throat aspirates for trichomonads and blood smears for Hemoproteus. If tests are negative, do not administer any medications. Evidence suggests that some drugs may cause immunosuppression. 3. During quarantine, vaccinate all new acquisitions for paramyxovirus 1 (PMVl). Salmonella vaccination is optional and is of questionable efficacy. Vaccination for pigeonpox is ideally done after the other vaccines, because birds will have an active case of pox that may decrease the immune response to the other vaccines if they are given concurrently. However, some practitioners administer all three vaccines at the same time with no apparent ill effects. 4. Vaccinate all young birds at least 6 to 8 weeks before racing or show season. Do not add unvaccinated birds to the flock at this time because they may contract clinical poxvirus infection. 5. Keep the pigeons in a clean, dry, well-ventilated loft. Do not overcrowd. Feed the birds according to their needs. If problems arise, seek a diagnosis prior to administering medications. VIRAL DISEASES
Viral disease is probably much more common than actually diagnosed in pigeons. Most infections cause only mild illness, but subclinical infections may complicate the disease processes caused by other pathogens. Because the presence of viruses is usually confirmed on necropsy, other pathogens (e.g., protozoa, gram-negative bacteria) are more likely to be implicated as the etiologic agents. Excluding paramyxovirus (PMVl) and pigeon pox Virus, herpes virus and adenovirus are the most notable pathogens. However, reovirus, rotavirus, togavirus, arbovirus, and influenza virus infections have been suggested as causes of immune system compromise. Pigeon Herpesvirus
Many pigeons are immune carriers of the herpesvirus (PHV) and, once infected, are life-long carriers, sometimes shedding without clinical
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signs. Young birds are most susceptible to clinical illness, but immunocompromised older birds may show symptoms. A mild to necrotizing pharyngitis and especially esoghagitis are the primary symptoms. Diphtheritic membranes and general signs of illness, including neurologic symptoms, green droppings, and anorexia, may be suggestive of PHV infection. Vomiting with no other symptoms in young birds and inclusion body hepatitis may occur. Adenovirus
Adenovirus infection has been shown to cause primary illness in pigeons. Young birds are most susceptible, and the symptoms are as would be expected with hepatic necrosis of any cause. Treatment is supportive. Antibiotics are indicated for prevention of secondary bacterial infection. Protozoal and helminth parasites should be eliminated and adequate hydration and nutrition provided. Paramyxovirus
Although it has been a problem in Europe and many other parts of the world for a long time, PMVI has been a problem in North America since 1984, and has spread over the whole continent since 1987 or 1989. Fanciers with absolutely closed flocks are at the lowest risk; those who race their pigeons frequently, buy, sell, trade, or allow contact with feral pigeons are most likely to have infected flocks. The primary symptoms are polyuria (not diarrhea) and central nervous signs ranging from incoordination, difficulty picking up grains, and mild head tilt to severe ataxia and torticollis. Surprisingly, affected pigeons do not seem to feel very ill, and most will eventually recover if given long-term supportive care. The most severely affected birds will be unable to feed well enough to maintain body weight, and euthanasia may be in order. Immune carriers are possible, and old and especially young birds are most susceptible to infection. Viral shedding may precede clinical signs, and incubation has been suggested as 1 week to as long as 6 weeks. The author recommends expedient vaccination of all birds, including young birds, in the face of an outbreak. Devastation in outbreaks has been minimized by vaccination, suggesting that incubation is long (2-4 weeks) or other factors cause a moderate to slow spread in a flock. Elimination of parasites, good nutrition, and loft cleanliness promote the strength of the pigeons immune system. Vaccination 1 to 2 months before breeding season and 6 to 8 weeks before racing or showing with the oil emulsion vaccine sub Q is recommended. The author vaccinates his young bird racing team upon weaning. The Lasota oral vaccine should not be depended upon for adequate protection.
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Pox
Pox virus is found in saliva and in nasal and lacrimal secretions. It enters the body through defects in the skin, especially on the wattle or cere. Direct contact, insect vectors, or airborne secretions may spread the disease. Scabs and proliferations of the cere, wattle, legs, feet, and commissures of the beak occur. The first symptoms may be a conjunctivitis with excess lacrimation and swelling of the eye cere. A diphtheroid form may occur, causing lesions on the mucosal surfaces inside the mouth. Secondary bacterial invasion may cause proliferative lesions, obstructing respiration and making eating difficult. Treatment of infected birds is strictly supportive. Preventitive measures including practicing strict sanitation, providing proper nutrition, using antibiotics, anthelmintics, and coccidiostats, should be taken in the event of an outbreak. Isolation of infected individuals and insect control using screens or insecticides may slow the spread. Birds develop an immunity 3 to 4 weeks after administration of a commercially available vaccine. Feathers are pulled, and the vaccine is applied by a dropper or a brush. The wing web is an acceptable site. An inflammatory reaction at the site suggests successful vaccination. Birds as young as 4 weeks of age may be vaccinated, and annual vaccination is recommended 4 weeks before the mosquito season. Care should be taken not to introduce new birds into an already vaccinated loft. The incidence of pox varies greatly from year to year and by geographic area. Late summer and fall, especially in years when the first freeze comes late, will increase the chances of an outbreak. BACTERIAL INFECTIONS j,.
The most important bacterial disease of pigeons ~hd doves is paratyphoid, caused by Salmonella typhimurium var. Copenhagen. The best known symptom is swollen wing and leg joints ("boils"), which should be considered almost pathognomonic by the practitioner when observed. However, most pigeons with paratyphoid will present with an array of other symptoms, including anorexia, weight loss, ruffled feathers, dropped wings, refusal to fly, diarrhea, green droppings, reproductive problems such as embryonic or early squab death, or death of older birds. Diagnosis is made by demonstration of the organism from the live bird or on necropsy. Selenite broth onto MacConkey's or brilliant green agar are suitable for recovering the organism from intestinal or crop contents. Treatment should be determined by sensitivity testing, because many strains exist with variable drug susceptibility. Enrofloxacin has demonstrated the most consistent efficacy record, although members of the penicillin, tetracycline, and aminoglycoside families sometimes may be suitable choices.
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Prevention is far superior to treatment. Before introducing new stock into a disease-free loft, birds should be quarantined in individual cages until they have raised a nest of healthy young. Cleanliness, acidification of floor litter, and strict control of stray pigeons are also helpful. Vaccination with a killed bacterin may be beneficial. Colibacillosis is another important problem in pigeons. Disease syndromes previously attributed to paratyphoid have recently been shown to be caused by E. coli when proper diagnostic tests were done. Excluding the swollen wing and leg joints, the symptoms of the two diseases are very similar. Other bacteria, such as Streptococcus, Staphylococcus, Pasteurella, Hemophilus, and Pseudomonas, have been described as pathogens but are of lesser importance than Salmonella and E. coli. Treatment of all bacterial diseases should involve cultures and sensitivity testing. Often, fanciers and veterinarians will "shotgun" flocks with antibiotics, resulting in many resistant strains of bacteria and many immunosuppressed pigeons. The Ornithosis Complex
The ornithosis complex ("eye colds" or "one-eyed roup" ) is common in domestic pigeons. Chlamydia is the primary etiologic agent, but Mycoplasma and gram-negative bacteria are also involved. Many herpesvirus infections are also complicated with chlamydia, so viral agents should probably be included in the complex. Frequently the same eye of all affected birds is in the windward side of wind currents. Treatment is usually successful with tylocin, but tetracyclines, lincomycin, or erythromycin may also be effective. Intramuscular injection is very irritating and should be avoided in racing birds. Oral administration and sinus flushing of antibiotics may be the best methods of treatment. Supportive therapy will reduce stress and enhance immune response. Topical ophthalmic medications also may be of benefit. PARASITIC DISEASES Endoparasites
Nematodes are the primary endoparasitic problems of pigeons. Ascarids, Capillaria, Tetrameres, Ornithostrongylus, and Dispharnyx are of concern; geographical location will determine the particular species that a clinician will encounter. Cestodes are occasionally encountered, and trematodes are rarely, if ever, found in the United States. Diagnosis is made by fecal flotation, direct smears, or intestinal or proventricular scrapings on necropsy. Cestode proglottids may be shed after food deprivation. Since cestodes and some nematodes such as Tetrameres require intermediate hosts, e.g., pill bugs, care should be taken
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to prevent pigeons from foraging where these inse!;Js are found. Raised lofts are the most common site where pigeons are infected. Piperazine is effective only for ascarids. Fenbendazole and mebendazole are effective for ascarids, Capillaria, and probably the others but must be used for 3 days. Levamisole is effective against ascardis and has some value against Capillaria. Ivermectin is most effective against all nematodes, but other drugs may be better for ascarids (e.g., pyrantel pamoate). Praziquantel is the drug of choice for cestodes and trematodes. Ectoparasites
Pigeon flies, lice, and mites are the most significant ectoparasites of pigeons. Pseudolynchia carariensis, the pigeon louse fly, seldom flies. It spends most of its time feeding on the bird's blood, causing anemia and transmission of Hemoproteus. Louse flies cause considerable discomfort to the bird and can be devastating to the general health of a flock. Columbicola columbae, the slender pigeon louse, is the most common mallophagian parasite. It does not take blood but feeds on feathers, causing tiny pinpoint holes. When lice are found by the clinician, other diseases should be considered. Heavy louse infestations usually indicate a debilitated bird that may not feel well enough to groom properly. Dermanyssus gallinae and possibly Ornithonyssus sylvarum cause skin irritation and feed on blood. They are called red mites or roost mites and are found on the bird at night. Knemidocoptes mutans, the scaly leg mite, causes considerable skin damage. Ivermectin is very effective for ectoparasites that feed on blood and body tissues and is recommended, along with dusting or preferably dipping with pyrethin products. Ivermectin and pyrethin are effective ·> if:against lice when used topically. ~.';·
Coccidia
The role of coccidia as a primary pathogen remains controversial, as oocyst shedding is commonly found in healthy birds. Often, pigeons afflicted with other diseases or under stress will shed large numbers of oocysts, particularly young birds. The physical examination should not end when fecal flotations reveal oocysts but should be thorough in eliminating bacterial pathogens, trichomoniasis, nutrititional deficiencies, husbandry errors, helminths, and so forth. Evidence indicates that low-level exposure to mildly virulent strains of coccidia may help produce immunity to more pathogenic strains. Many considerations should be taken into account before instituting therapy with coccidiostatic drugs. When a disease situation involving coccidia occurs and drugs must be used, sanitation and good husbandry to prevent fecal-oral contact should be the first therapy instituted. Heavily bred or heavily raced older
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birds and young birds kept under less than optimal conditions are the most susceptible to disease. Clazoril, amprolium, sulfachlorpyridazine, and other sulfas such as sulfadimethoxine and sulfamethazine are effective coccidistats. Vitamin B supplementation after therapy is beneficial. Nitrofurazone may help with secondary bacterial enteric infections but is not recommended for coccidiosis in pigeons. Three to 5 days are required for the oocyst to sporulate and become infective, so frequent cleaning is the best preventitive measure. Trichomoniasis
Most pigeons and doves carry Trichomonas gallinae. This parasite can be a primary pathogen or cause disease secondary to other illnesses or stressful conditions. The severity of trichomoniasis depends on the virulence of the strain and the magnitude of debility from concurrent diseases. The common name "canker" refers to the cheesy, white caseous deposits in the throat of birds with advanced disease. More often the condition is confused with respiratory disease because the oculo-nasal and oral discharges are clear. The organism can easily be demonstrated by suctioning the mucus from the throat and immediately observing the sample with immersion microscopy. Trichomonas often accompanies the ornithosis complex, viral illnesses, parasitic diseases and noninfectious stressful situations. Successful therapy involves resolving the other diseases as well as treatment of the trichomonads. The immune status of the bird is very important to consider if recovery is to be expected. Exposure to strains of low virulence in an immunocompetent bird may produce resistance against pathogenic strains. Although primarily a disease of the upper alimentary tract, local lesions, including omphalitis, may occur as well as infection of liver, lung, and other organs. Effective treatment involves proper use of the 5-nitroimidazole derivatives, including ronidazole, carnidazole, dimetridazole and metronidazole. Prevention is dependent upon reducing stress and controlling other diseases. Total eradication of the organism is not practical or desirable. Hemoproteus
"Pigeon malaria" is the name frequently given to hemoproteus infection, but Plasmodium spp are rarely reported in pigeons. It is much more common in performing breeds than in fancy or utility pigeons. This may be because the stresses and exposure to insect vectors in racing situations make the disease more apparent in racing pigeons than in sedentary exhibition pigeons. The disease is transmitted by the pigeon
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fly. Hemoproteus infection is diagnosed by demonstration of the organism in the red blood cell's cytoplasm without nucl~ar displacement, as shown on stained blood smears. Control of insect vectors is the best prevention. Dusting with pyrethin every 2 weeks may be effective in controlling pigeon flies in endemic areas. The disease has been effectively treated with quinacrine. Primaquin has been successfully used as a preventive.
Hexamita
Hexamitiasis primarily occurs in young pigeons. Symptoms include weight loss, diarrhea, and general unthriftiness, and demonstration of the organism on very fresh direct fecal smears is diagnostic. The nitroimidazole derivatives, carnidazole, dimetridazole, ronidazole, and metronidazole, are the most effective antiprotozoal drugs. Carnidazole is the drug of choice. Preventing fecal-oral contact is helpful in controlling hexamitiasis.
PIGEON FORMULARY Sulfadimethoxine
This drug has similar activity against coccidia and bacteria except its half life is longer than other sulfas in the pigeon. The dosage is 1250 to 1500 mg/ gallon of drinking water on the first day, followed by 750 to 1000 mg. for 4 days. Supplement B vitamins 5 days and re-treat as necessary. Adjust environment to av¥-reinfection. ~:-.
Sulfamethazine
Sulfamethazine is frequently used by fanciers for intestinal disease due to its coccidiostatic properties. The dosage is 1500 mg/ gallon on the first day, followed by 750 to 1000 mg per gallon for 4 days. Supplement B vitamins 5 days, then re-treat. Follow-up fecal flotations will confirm if further therapy is indicated.
Trimethoprim/Sulfadiazine or Sulfamethoxazole
These ~re effective in m~~y infectious diseases of pigeons involving as well as coccidia. The dosage 1s 60 mg/ kg b1d orally. Gtve 1800 mg to 3600 mg/ gallon of drinking water for 7 to 10 days. ~ram-negative ~nd gram-p~s1hve bacteria
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Tylocin
Tylocin is a bacteriostatic and mycoplasmastatic macrolide antibiotic with little or no gram-negative spectrum. It is probably the drug of choice for the ornithose complex, especially when used in combination with other drugs such as tetracyclines. It is very irritating to muscles when injected, so it should be used with care in patients with a future racing career. It has very little potential for toxicity, and bolus doses of three or four times recommended dosage have been used orally with good clinical results when more frequent administration was not possible. The dosage is 25 to 50 mg/kg IM or SQ bid, 3 g/per gallon of drinking water (2 tsp ).
Quinacrine
This is an antimalarial compound used to control Hemoproteus. The dosage is 1 to 3 tablets/ gallon for 10 to 21 days.
Ronidazole
This 5-nitro-imidazole compound is not available in the United States. It is probably the drug of choice for protozoal diseases due to ease of administration to flocks, lack of toxicity, and good effect. The dosage is 400 mg/gallon for 3 to 5 days (1/2 to 3/4 tsp).
Spectinomycin
Spectinomycin is a broad-spectrum antibiotic similar to the aminoglycosides. It has good gram-negative spectrum, especially against E. coli. Although it is very poorly absorbed orally, it is quite useful in stopping the spread of disease in a flock when administered in the drinking water. The drug must be injected in clinically ill birds and is often effective in gram-negative bacterial infections. It has less nephrotoxicity than aminoglycosides. Dosage is 25 to 35 mg/kg bid or tid IM, 600 mg to 1000 mg/ gallon of drinking water.
Sulfachlorpyridazine
This bacteriostatic antimicrobial has a broad spectrum. It is very effective against E. coli and a good coccidiostat. Sulfachlorpyridazine is an excellent choice when coccidia and secondary bacterial enteritis is apparent. The dosage is 1200 mg/ gallon for 7 to 10 days.
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Piperazine
This is effective only against Ascarids. The dosage is 35 mg/ kg for 2 days, 300 mg/ gallon for 2 days. Primaquine
This 8-aminoquinoline compound is used to control Hemoproteus in pigeons. It will not cure but does suppress the organism and alleviates symptoms in the patient. The dosage is 1 to 2 tablets/ gallon for 10 to 21 days before race season, then 1 to 2 days weekly. Controlling pigeon flies is probably the most important factor in controlling Hemoproteus in problem areas.
Pyrantel Pamoate
This is excellent and safe for individual dosing for Roundworms, given as 20 to 25 mg/ kg PO, 50 mg/mL liquid. Pyrethrin, Permethrin
Dusts and dips are quite effective against mites and lice. Heavy louse burdens indicate underlying causes. Dosage is liberal powdering under wings and over dorsal aspect of bird and vent area. Mix cat dip preparation containing pyrethrin and permethrin at a 50% greater dilution with 2 drops/ gallon of dishwashing detergent. Supmerge bird to neck level on a warm day. Allow no baths for a we~k ~.OSo; e.g., 2 oz. dip to 3 gallons water with 6 drops of detergent. · Lincomycin
This is a macrolide antibiotic with a similar spectrum to tylocin. It clinically is not as effective as tylocin in pigeon respiratory disease. It is often used orally in combination with spectinomycin and is useful in nasal flushes for sinus problems. The dosage is 25 to 50 mg/kg IM. Mebendazole
Mebendazole is a benzamidazole anthelmintic that is effective against most pigeon worms except cestodes. Dosage is 5 to 6 m g / kg for 3 to 5 days, 1/ 4 to 1/2 teaspoon per gallon of dog wormer preparation for 3 to 5 days.
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Metronidazole
This 5-nitro-imidazole compound is quite effective against protozoa and anaerobic bacteria, but it is not often used for flock treatment due to poor solubility. Dosage is 200 to 250 mg/kg daily for 3 to 7 days PO, 4000 mg per gallon of drinking water for 3 to 7 days. Nystatin
Candidiasis is usually secondary to prolonged antibiotic use. Nystatin is not well absorbed but may stop the replication of yeasts in the crop and lower G.I. tract. Crop stasis (sour crop) is usually due to severe lower intestinal disease. The dosage is 100,000 units per kg bid PO. Piperacillin
Its activity is similar to carbenicillin, but it is often more effective against Pseudomonas. It is the drug of choice for critically ill patients with intestinal disease. Often, piperacillin is used in combination with other antibiotics such as aminoglycosides and quinolones. It is effective in many anaerobic infections, as are other penicillins. Dosage is 100 mg/kg IM bid or tid. Enrofloxacin
This bacteriocidal quinolone chemotherapeutic agent is rapidly absorbed and penetrates body tissues well. It is excellent in respiratory infections, and it is the drug of choice for Salmonella typhimurium infections. Some adverse effects have been reported in breeding hens and squabs. It is the most likely drug to eliminate paratyphoid carrier states. Dosage is 12 to 15 mg/kg bid PO 7 to 14 days, 150 to 600 mg per gallon of drinking water for 7 to 14 days. Erythromycin
This macrolide is similar to tylocin and lincomycin. It is very irritating to muscles when injected. Dosage is 125 mg/kg tid PO, 2 to 3 g/ gallon of drinking water. Fenbendazole
Fenbendazole is a benzamidizole anthelmintic that is effective against ascarids, Capillaria, strongyles, and Tetrameres. Feather abnor-
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'· malities have been reported when it is used during the moult. The dosage is 10 to 12 mg/kg PO sid for 3 days. .,., lvermectin
This very safe and effective anthelmintic is the wormer of choice except for tapeworms and ascarids. Ivermectin is also effective for mites and lice that feed on body tissues. It is effective for feather lice when sprayed topically. The dosage is 0.5 mg to 1 mg/ kg PO or injected. Levamisole
Levamisole is very effective against ascarids and moderately effective against other nematodes. It may cause vomiting after administration. Dosage is 40 mg/kg PO once or 1000 to 1500 mg/ gallon of drinking water for 24 hours. Dimetridazole
This water-soluble 5-nitro-imidazole derivative has very good antiprotozoal activity. It is quite toxic if overdosed, causing dose-related central nervous system symptoms. The dosage is 1/ 2 to 1 tsp gallon for the (U.S. product), which is no longer available. The dosage is 1/ 4 to 1/2 tsp gallon 3 to 5 days for the Mexican or Canadian product. Doxycycline
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Doxycycline is the drug of choice for chlamydiosis. It is far superior to other tetracyclines, but it requires individual bird dosing. Dosage is 25 to 50 mg/kg PO bid. Cephalexin
Cephalexin is bacteriocidal by cell wall inhibition, similar to penicillins. It probably has little advantage over penicillins except where sensitivities indicate or when Staphylococcus is suspected. Dosage is 100 mg/ kg bid or tid PO. Chloramphenicol
. This very bro~d-spectrum bacteriostatic antibiotic reaches all body hssues well mcludmg the central nervous system. It is one of the best
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drugs for Salmonella in human medicine. Chlamydostatic properties and good gram-negative spectrum make it useful in treating conjunctivitis in respiratory conditions and eye injuries with ophthalmic drops. It is quickly excreted in the pigeon, making mean inhibitory concentrations difficult to attain. Dosage is 60 to 100 mg/kg IM tid, 250 mg/ kg PO qid, ophthalmic drops tid or qid. Chlortetracycline and Oxytetracycline
These drugs are frequently used by fanciers for respiratory disease. They are probably effective due to high incidence of chlamydia! infections in pigeons and are best used in combination with tylocin in Ornithose complex. Absorption is inhibited by the presence of calcium in the intestinal tract, so grit and layer pellets should be withheld during treatment. When offered in drinking water in warm weather, it should be freshly mixed at least twice daily. The dosage is 50 mg/kg tid or qid PO, 1000 mg to 1500 mg/ gallon of drinking water. Clazoril
This coccidiostat has the advantage of stopping oocyst shedding for prolonged periods after single tablet administration. Dosage is 5 mg/ kg PO or one 2.5 mg tablet per Racing Homer-size bird. Carnidazole
This very safe 5-nitro-imidazole antiprotozoal compound is the only drug labeled for use in pigeons in the United States. Dosage is 20 mg/ kg PO. Cefadroxil
Cefadroxil has similar activity to cephalexin but may have a longer half-life in birds. Its dosage is 100 mg/kg, bid PO. Cefataxime
This third-generation cephlosporin has an excellent gram-negative spectrum, especially against E. coli. The dosage is 100 mg/ kg IM bid or tid. Ceftidime
Although similar to cefataxime, ceftidime may be more effective against Pseudomonas. It is a possible drug of choice in pneumonia due to excellent levels in the lungs. Its dosage is 100 mg/ kg IM bid or tid.
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Aminoglycosides
Streptomycin, kanamycin and neomycin have no place, especially systemically, in pigeon medicine. Amikacin and gentamicin are useful, especially in nasal flushes and ophthalmic preparations against Pseudomonas and other difficult aerobes. They are probably quickly excreted from the pigeon's body, and their toxic properties are well known in other birds and animals, so they are seldom used systemically. They are not absorbed orally but may have some use in eliminating undesirable intestinal flora. The dosage is 1 drop qid for ophthalmic disease. Amoxicillin
Amoxicillin is well-absorbed and nontoxic in pigeons. It is recommended for many bacterial infections and is probably the drug of choice for animal bite wounds and postsurgical wound care. It is effective in some cases of salmonellosis and colibacillosis. Dosage is 100 mg/kg bid PO or 2 to 3 g / gallon of drinking water. Amoxicillin with Clavulinic Acid
This combination is nearly the same as Amoxicillin but has a much better spectrum against Staphylococcus. Probably, it has no advantages over amoxicillin unless sensitivities dictate. Dosage is 125 mg/ kg bid PO. Amprolium
This chemical ties up thiamine, inhibiting replicc;J.tidi\:""It is a very effective coccidiostat and, in the absence of clinical disease, is probably the best choice if all that is desired is to stop oocyst shedding. Dosage is 1 tsp /gallon of 20% powder, 8 mL/gallon of9.64% solution for 3-5 days. Carbenicillin
Carbenicillin is a bacteriocidal injectable w ith greater gram-negative spectrum than am oxicillin. Dosage is 100 m g / kg IM bid or tid in critically ill patients. Suggested Readings Annual Proceedings of the Association of Pigeon Veterinarians (APV). Contact the author at the address at the end of this article for information on joining the APV. Harlin RW: Pigeons. In Rosskopf WJ, Woerpel R: Petrak's Cage and Aviary Birds. Malvern, Lea & Febiger, in press
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Muller E, Schrag L: Fancy Pigeons. Hengersberg, Germany, Schober Verlags, 1985 Tudor DC Pigeon Health and Disease. Ames, lA, Iowa State University Press, 1991 Wages DP: Diseases of Pigeons. Vet Clin North Am Small Anim Pract 17:1089, 1987
Address reprint requests to Roger W. Harlin, DVM Southside Dog, Cat, and Bird Hospital 7020 South Shields Oklahoma City, OK 73149
0195-5616/94 $0.00 + .20
PIGEONS Roger W. Harlin, DVM
The association of humans with pigeons and doves dates back to as early as 3000 to 5000 B.C. Other birds were bred for meat and egg production, but pigeons are thought to have been kept to aid agriculture. Their ability to fly long distances, select the richest nutrients, and then return to the same nesting place made their droppings an easily collectible source of rich fertilizer for growing crops in arid climates and on infertile land. As time went on, humans found more uses for pigeons. Best known is the part they played in communication during wartime before the invention of the wireless. Throughout history, the more advanced the civilization, the closer the association of humans with pigeons and doves. Pigeons are classified as flying and performance, fancy, or utility pigeons. There are standards of perfection for exhibition of almost 300 breeds of fancy pigeons. All breeds are derived from the common rock dove (Columba livia). Most of the pigeons kept are Racing Homers, trained to compete in the sport of racing. Other breeds, such as Tipplers, High Flyers, Rollers, Nose Divers, and Doneks, are bred for their aerial acrobatic abilities. Pigeon meat, or squab, is still considered a delicacy in many parts of the world. Some utility breeds are capable of producing 12 to 16 pounds of meat yearly. In contrast, other breeds produce four to six young per year. PHYSIOLOGY AND REPRODUCTION
Although pigeons usually mate for life, most birds will readily take a new mate after a short period of separation. A system of polygamous From Southside Dog, Cat, and Bird Hospital, Oklahoma City, Oklahoma
VETERINARY CLINICS OF NORTH AMERICA: SMALL ANIMAL PRACTICE VOLUME 24 • NUMBER 1 • JANUARY 1994
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breeding called the "bull system" is often used to breed numerous hens to a prepotent cock. Eggs are fostered to feeder 'pairs. This system may yield two babies from the favored cock every 2 to 3 weeks, whereas natural pair methods will yield two youngsters at most every 6 to 7 weeks. The breeding season is in the spring. Pigeons lay two eggs about 40 hours apart. Incubation is 17 to 19 days. The cock assists in incubation from late morning to mid-afternoon. Several days before the eggs hatch, "crop milk" formation is stimulated by prolactin secreted from the pituitary gland. An actual desquamation of the crop epithelium, crop milk is very rich in protein and fats and is all that squabs receive from the parents for the first week. During the second week, grains and other food are regurgitated by the parents, and the production of crop milk ceases. The cock plays a role equal to or greater than that of the hen in feeding the squabs, particularly if the hen has begun incubation of the next clutch before the squabs have been removed to a weaning pen. Weaning occurs naturally at about 4 weeks of age. Some fanciers believe that earlier weaning makes for a more resourceful older bird. Others prefer to leave the squabs in the nest longer, believing that extra help from the parents is beneficial. A pair typically produces two to three clutches per season. Pigeons reach maturity between 5 and 12 months of age, depending on breed and birth date. Toy breeds born early will mature faster than late-hatch giant breeds. Mature body weight ranges from 150 to 180 g in breeds such as the African Owl to over 1400 g in the American Giant Runt. Most Racing Homers weigh about 360 to 480 g. Pigeons have paired vestigial ceca and no gall bladder. The normal white blood cell count ranges from 8000 to 18,000 cells/mm3 and is generally 12,000 to 15,000/mm3 • The normal red blood cell count is 3 million to 4 million/mm3 • Total protein should be between 2 to 4 mg/dL. Body temperature is about 105° F.
HOUSING
Pigeon houses are called lofts. Pigeons do not require elaborate facilities; however, the birds will be more comfortable and productive if a loft is designed specifically for breeding, racing, or whatever the fancier is trying to accomplish. Lofts must be dry. Pigeons can tolerate extreme temperatures, but moisture and dampness will certainly result in illness and poor performance. Lofts must be well-ventilated but without direct drafts. Respiratory problems are seen in pigeons kept in tightly closed structures in which the air is stale and dust builds up. The ideal loft is built 1 to 2 feet above dry ground with wire floors. Ceiling vents provide good ventilation. A wire floor prevents direct contact with the droppings. Sand, cedar shavings, and many other litters ha~e been used s~cce~sfully. Some fanciers use a natural litter (dropping buildup), and their birds do well. The natural litter must be absolutely
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dry and should be used only in a closed flock. Generally, the cleaner the loft, the healthier the birds. However, there is evidence that a completely sterile loft is not optimum, because low-level contact of healthy birds to avirulent strains of coccidia helps to maintain immunity. Pigeons love to "own" property and raise families. It is this love of mate, loft, nest, and perch space that inspires them to excel as avian athletes. They will fly hundreds of miles under any conditions to be "home." Too many birds in too small a place will destroy their morale. Overcrowding is the worst enemy of pigeon health. The fancier must judge if certain pigeons are affecting the quality of life of others. Sometimes "troublemakers" may have to be removed from a particular pigeon society. Happy pigeons in clean, well-ventilated lofts are generally healthy pigeons that seldom require medication. NUTRITION
Proper nutrition is essential if pigeons are to maintain good form and resistance to disease. Nutritional requirements vary greatly according to season, moulting, growth, breeding, and the demands of performance or racing. Simple logic and common sense suggest that increased protein is important to growing squabs and is not as important to inactive birds in winter. More carbohydrates are beneficial in wintering birds in cold climates, because caloric needs will be increased. Higher fats and protein are helpful during the moult to enhance feather quality and growth. Racing demands a judicious feeding schedule. The requirements will vary with distance and race conditions. For instance, more fats may help a bird to fly 500 miles in headwinds, whereas more carbohydrates and being a bit hungry may enhance the performance of a 150-m* sprinter. There are a number of commercial pelleted rations and blends of grains. Following the instructions and recommendations of reputable companies is usually satisfactory. However, most fanciers have their own ideas and will make additions and corrections to commercial products. Austrian, maple, and Canadian peas are among the best protein seeds. Safflower seeds and Spanish peanuts are often used to supplement fats before races. Barley, wheat, and corn are good carbohydrate grains for winter. These grains are usually included in mixtures in varying amounts along with milo, kaffir, millet, oat groats, and many others. Grit can be offered, although it is probably not necessary. Many minerals are available in the balanced pelleted rations. An unsupplemented breeder diet of only grains, without calcium, vitamins, and trace minerals, will most likely result in defective squabs. PREVENTIVE MEDICINE
Medications will rarely be necessary if these guidelines are followed by the pigeon fancier.
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1. Buy quality stock from a quality breeder. Do not introduce new
birds into_an existing healthy flock until they have been quarantined and physically examined. The optimum length of quarantine is the time for a pair to raise two or three sets of babies. When quarantine is over, introduce one pair at a time to the existing flock. Allow each pair to establish territory before adding the next pair. This method minimizes the stress of pairs finding a place in the loft. 2. Examine all new birds for ectoparasites such as lice, mites, and pigeon flies. Perform fecal flotation and direct smears to check for helminths and coccidia. Examine throat aspirates for trichomonads and blood smears for Hemoproteus. If tests are negative, do not administer any medications. Evidence suggests that some drugs may cause immunosuppression. 3. During quarantine, vaccinate all new acquisitions for paramyxovirus 1 (PMVl). Salmonella vaccination is optional and is of questionable efficacy. Vaccination for pigeonpox is ideally done after the other vaccines, because birds will have an active case of pox that may decrease the immune response to the other vaccines if they are given concurrently. However, some practitioners administer all three vaccines at the same time with no apparent ill effects. 4. Vaccinate all young birds at least 6 to 8 weeks before racing or show season. Do not add unvaccinated birds to the flock at this time because they may contract clinical poxvirus infection. 5. Keep the pigeons in a clean, dry, well-ventilated loft. Do not overcrowd. Feed the birds according to their needs. If problems arise, seek a diagnosis prior to administering medications. VIRAL DISEASES
Viral disease is probably much more common than actually diagnosed in pigeons. Most infections cause only mild illness, but subclinical infections may complicate the disease processes caused by other pathogens. Because the presence of viruses is usually confirmed on necropsy, other pathogens (e.g., protozoa, gram-negative bacteria) are more likely to be implicated as the etiologic agents. Excluding paramyxovirus (PMVl) and pigeon pox Virus, herpes virus and adenovirus are the most notable pathogens. However, reovirus, rotavirus, togavirus, arbovirus, and influenza virus infections have been suggested as causes of immune system compromise. Pigeon Herpesvirus
Many pigeons are immune carriers of the herpesvirus (PHV) and, once infected, are life-long carriers, sometimes shedding without clinical
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signs. Young birds are most susceptible to clinical illness, but immunocompromised older birds may show symptoms. A mild to necrotizing pharyngitis and especially esoghagitis are the primary symptoms. Diphtheritic membranes and general signs of illness, including neurologic symptoms, green droppings, and anorexia, may be suggestive of PHV infection. Vomiting with no other symptoms in young birds and inclusion body hepatitis may occur. Adenovirus
Adenovirus infection has been shown to cause primary illness in pigeons. Young birds are most susceptible, and the symptoms are as would be expected with hepatic necrosis of any cause. Treatment is supportive. Antibiotics are indicated for prevention of secondary bacterial infection. Protozoal and helminth parasites should be eliminated and adequate hydration and nutrition provided. Paramyxovirus
Although it has been a problem in Europe and many other parts of the world for a long time, PMVI has been a problem in North America since 1984, and has spread over the whole continent since 1987 or 1989. Fanciers with absolutely closed flocks are at the lowest risk; those who race their pigeons frequently, buy, sell, trade, or allow contact with feral pigeons are most likely to have infected flocks. The primary symptoms are polyuria (not diarrhea) and central nervous signs ranging from incoordination, difficulty picking up grains, and mild head tilt to severe ataxia and torticollis. Surprisingly, affected pigeons do not seem to feel very ill, and most will eventually recover if given long-term supportive care. The most severely affected birds will be unable to feed well enough to maintain body weight, and euthanasia may be in order. Immune carriers are possible, and old and especially young birds are most susceptible to infection. Viral shedding may precede clinical signs, and incubation has been suggested as 1 week to as long as 6 weeks. The author recommends expedient vaccination of all birds, including young birds, in the face of an outbreak. Devastation in outbreaks has been minimized by vaccination, suggesting that incubation is long (2-4 weeks) or other factors cause a moderate to slow spread in a flock. Elimination of parasites, good nutrition, and loft cleanliness promote the strength of the pigeons immune system. Vaccination 1 to 2 months before breeding season and 6 to 8 weeks before racing or showing with the oil emulsion vaccine sub Q is recommended. The author vaccinates his young bird racing team upon weaning. The Lasota oral vaccine should not be depended upon for adequate protection.
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Pox
Pox virus is found in saliva and in nasal and lacrimal secretions. It enters the body through defects in the skin, especially on the wattle or cere. Direct contact, insect vectors, or airborne secretions may spread the disease. Scabs and proliferations of the cere, wattle, legs, feet, and commissures of the beak occur. The first symptoms may be a conjunctivitis with excess lacrimation and swelling of the eye cere. A diphtheroid form may occur, causing lesions on the mucosal surfaces inside the mouth. Secondary bacterial invasion may cause proliferative lesions, obstructing respiration and making eating difficult. Treatment of infected birds is strictly supportive. Preventitive measures including practicing strict sanitation, providing proper nutrition, using antibiotics, anthelmintics, and coccidiostats, should be taken in the event of an outbreak. Isolation of infected individuals and insect control using screens or insecticides may slow the spread. Birds develop an immunity 3 to 4 weeks after administration of a commercially available vaccine. Feathers are pulled, and the vaccine is applied by a dropper or a brush. The wing web is an acceptable site. An inflammatory reaction at the site suggests successful vaccination. Birds as young as 4 weeks of age may be vaccinated, and annual vaccination is recommended 4 weeks before the mosquito season. Care should be taken not to introduce new birds into an already vaccinated loft. The incidence of pox varies greatly from year to year and by geographic area. Late summer and fall, especially in years when the first freeze comes late, will increase the chances of an outbreak. BACTERIAL INFECTIONS j,.
The most important bacterial disease of pigeons ~hd doves is paratyphoid, caused by Salmonella typhimurium var. Copenhagen. The best known symptom is swollen wing and leg joints ("boils"), which should be considered almost pathognomonic by the practitioner when observed. However, most pigeons with paratyphoid will present with an array of other symptoms, including anorexia, weight loss, ruffled feathers, dropped wings, refusal to fly, diarrhea, green droppings, reproductive problems such as embryonic or early squab death, or death of older birds. Diagnosis is made by demonstration of the organism from the live bird or on necropsy. Selenite broth onto MacConkey's or brilliant green agar are suitable for recovering the organism from intestinal or crop contents. Treatment should be determined by sensitivity testing, because many strains exist with variable drug susceptibility. Enrofloxacin has demonstrated the most consistent efficacy record, although members of the penicillin, tetracycline, and aminoglycoside families sometimes may be suitable choices.
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Prevention is far superior to treatment. Before introducing new stock into a disease-free loft, birds should be quarantined in individual cages until they have raised a nest of healthy young. Cleanliness, acidification of floor litter, and strict control of stray pigeons are also helpful. Vaccination with a killed bacterin may be beneficial. Colibacillosis is another important problem in pigeons. Disease syndromes previously attributed to paratyphoid have recently been shown to be caused by E. coli when proper diagnostic tests were done. Excluding the swollen wing and leg joints, the symptoms of the two diseases are very similar. Other bacteria, such as Streptococcus, Staphylococcus, Pasteurella, Hemophilus, and Pseudomonas, have been described as pathogens but are of lesser importance than Salmonella and E. coli. Treatment of all bacterial diseases should involve cultures and sensitivity testing. Often, fanciers and veterinarians will "shotgun" flocks with antibiotics, resulting in many resistant strains of bacteria and many immunosuppressed pigeons. The Ornithosis Complex
The ornithosis complex ("eye colds" or "one-eyed roup" ) is common in domestic pigeons. Chlamydia is the primary etiologic agent, but Mycoplasma and gram-negative bacteria are also involved. Many herpesvirus infections are also complicated with chlamydia, so viral agents should probably be included in the complex. Frequently the same eye of all affected birds is in the windward side of wind currents. Treatment is usually successful with tylocin, but tetracyclines, lincomycin, or erythromycin may also be effective. Intramuscular injection is very irritating and should be avoided in racing birds. Oral administration and sinus flushing of antibiotics may be the best methods of treatment. Supportive therapy will reduce stress and enhance immune response. Topical ophthalmic medications also may be of benefit. PARASITIC DISEASES Endoparasites
Nematodes are the primary endoparasitic problems of pigeons. Ascarids, Capillaria, Tetrameres, Ornithostrongylus, and Dispharnyx are of concern; geographical location will determine the particular species that a clinician will encounter. Cestodes are occasionally encountered, and trematodes are rarely, if ever, found in the United States. Diagnosis is made by fecal flotation, direct smears, or intestinal or proventricular scrapings on necropsy. Cestode proglottids may be shed after food deprivation. Since cestodes and some nematodes such as Tetrameres require intermediate hosts, e.g., pill bugs, care should be taken
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to prevent pigeons from foraging where these inse!;Js are found. Raised lofts are the most common site where pigeons are infected. Piperazine is effective only for ascarids. Fenbendazole and mebendazole are effective for ascarids, Capillaria, and probably the others but must be used for 3 days. Levamisole is effective against ascardis and has some value against Capillaria. Ivermectin is most effective against all nematodes, but other drugs may be better for ascarids (e.g., pyrantel pamoate). Praziquantel is the drug of choice for cestodes and trematodes. Ectoparasites
Pigeon flies, lice, and mites are the most significant ectoparasites of pigeons. Pseudolynchia carariensis, the pigeon louse fly, seldom flies. It spends most of its time feeding on the bird's blood, causing anemia and transmission of Hemoproteus. Louse flies cause considerable discomfort to the bird and can be devastating to the general health of a flock. Columbicola columbae, the slender pigeon louse, is the most common mallophagian parasite. It does not take blood but feeds on feathers, causing tiny pinpoint holes. When lice are found by the clinician, other diseases should be considered. Heavy louse infestations usually indicate a debilitated bird that may not feel well enough to groom properly. Dermanyssus gallinae and possibly Ornithonyssus sylvarum cause skin irritation and feed on blood. They are called red mites or roost mites and are found on the bird at night. Knemidocoptes mutans, the scaly leg mite, causes considerable skin damage. Ivermectin is very effective for ectoparasites that feed on blood and body tissues and is recommended, along with dusting or preferably dipping with pyrethin products. Ivermectin and pyrethin are effective ·> if:against lice when used topically. ~.';·
Coccidia
The role of coccidia as a primary pathogen remains controversial, as oocyst shedding is commonly found in healthy birds. Often, pigeons afflicted with other diseases or under stress will shed large numbers of oocysts, particularly young birds. The physical examination should not end when fecal flotations reveal oocysts but should be thorough in eliminating bacterial pathogens, trichomoniasis, nutrititional deficiencies, husbandry errors, helminths, and so forth. Evidence indicates that low-level exposure to mildly virulent strains of coccidia may help produce immunity to more pathogenic strains. Many considerations should be taken into account before instituting therapy with coccidiostatic drugs. When a disease situation involving coccidia occurs and drugs must be used, sanitation and good husbandry to prevent fecal-oral contact should be the first therapy instituted. Heavily bred or heavily raced older
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birds and young birds kept under less than optimal conditions are the most susceptible to disease. Clazoril, amprolium, sulfachlorpyridazine, and other sulfas such as sulfadimethoxine and sulfamethazine are effective coccidistats. Vitamin B supplementation after therapy is beneficial. Nitrofurazone may help with secondary bacterial enteric infections but is not recommended for coccidiosis in pigeons. Three to 5 days are required for the oocyst to sporulate and become infective, so frequent cleaning is the best preventitive measure. Trichomoniasis
Most pigeons and doves carry Trichomonas gallinae. This parasite can be a primary pathogen or cause disease secondary to other illnesses or stressful conditions. The severity of trichomoniasis depends on the virulence of the strain and the magnitude of debility from concurrent diseases. The common name "canker" refers to the cheesy, white caseous deposits in the throat of birds with advanced disease. More often the condition is confused with respiratory disease because the oculo-nasal and oral discharges are clear. The organism can easily be demonstrated by suctioning the mucus from the throat and immediately observing the sample with immersion microscopy. Trichomonas often accompanies the ornithosis complex, viral illnesses, parasitic diseases and noninfectious stressful situations. Successful therapy involves resolving the other diseases as well as treatment of the trichomonads. The immune status of the bird is very important to consider if recovery is to be expected. Exposure to strains of low virulence in an immunocompetent bird may produce resistance against pathogenic strains. Although primarily a disease of the upper alimentary tract, local lesions, including omphalitis, may occur as well as infection of liver, lung, and other organs. Effective treatment involves proper use of the 5-nitroimidazole derivatives, including ronidazole, carnidazole, dimetridazole and metronidazole. Prevention is dependent upon reducing stress and controlling other diseases. Total eradication of the organism is not practical or desirable. Hemoproteus
"Pigeon malaria" is the name frequently given to hemoproteus infection, but Plasmodium spp are rarely reported in pigeons. It is much more common in performing breeds than in fancy or utility pigeons. This may be because the stresses and exposure to insect vectors in racing situations make the disease more apparent in racing pigeons than in sedentary exhibition pigeons. The disease is transmitted by the pigeon
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fly. Hemoproteus infection is diagnosed by demonstration of the organism in the red blood cell's cytoplasm without nucl~ar displacement, as shown on stained blood smears. Control of insect vectors is the best prevention. Dusting with pyrethin every 2 weeks may be effective in controlling pigeon flies in endemic areas. The disease has been effectively treated with quinacrine. Primaquin has been successfully used as a preventive.
Hexamita
Hexamitiasis primarily occurs in young pigeons. Symptoms include weight loss, diarrhea, and general unthriftiness, and demonstration of the organism on very fresh direct fecal smears is diagnostic. The nitroimidazole derivatives, carnidazole, dimetridazole, ronidazole, and metronidazole, are the most effective antiprotozoal drugs. Carnidazole is the drug of choice. Preventing fecal-oral contact is helpful in controlling hexamitiasis.
PIGEON FORMULARY Sulfadimethoxine
This drug has similar activity against coccidia and bacteria except its half life is longer than other sulfas in the pigeon. The dosage is 1250 to 1500 mg/ gallon of drinking water on the first day, followed by 750 to 1000 mg. for 4 days. Supplement B vitamins 5 days and re-treat as necessary. Adjust environment to av¥-reinfection. ~:-.
Sulfamethazine
Sulfamethazine is frequently used by fanciers for intestinal disease due to its coccidiostatic properties. The dosage is 1500 mg/ gallon on the first day, followed by 750 to 1000 mg per gallon for 4 days. Supplement B vitamins 5 days, then re-treat. Follow-up fecal flotations will confirm if further therapy is indicated.
Trimethoprim/Sulfadiazine or Sulfamethoxazole
These ~re effective in m~~y infectious diseases of pigeons involving as well as coccidia. The dosage 1s 60 mg/ kg b1d orally. Gtve 1800 mg to 3600 mg/ gallon of drinking water for 7 to 10 days. ~ram-negative ~nd gram-p~s1hve bacteria
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Tylocin
Tylocin is a bacteriostatic and mycoplasmastatic macrolide antibiotic with little or no gram-negative spectrum. It is probably the drug of choice for the ornithose complex, especially when used in combination with other drugs such as tetracyclines. It is very irritating to muscles when injected, so it should be used with care in patients with a future racing career. It has very little potential for toxicity, and bolus doses of three or four times recommended dosage have been used orally with good clinical results when more frequent administration was not possible. The dosage is 25 to 50 mg/kg IM or SQ bid, 3 g/per gallon of drinking water (2 tsp ).
Quinacrine
This is an antimalarial compound used to control Hemoproteus. The dosage is 1 to 3 tablets/ gallon for 10 to 21 days.
Ronidazole
This 5-nitro-imidazole compound is not available in the United States. It is probably the drug of choice for protozoal diseases due to ease of administration to flocks, lack of toxicity, and good effect. The dosage is 400 mg/gallon for 3 to 5 days (1/2 to 3/4 tsp).
Spectinomycin
Spectinomycin is a broad-spectrum antibiotic similar to the aminoglycosides. It has good gram-negative spectrum, especially against E. coli. Although it is very poorly absorbed orally, it is quite useful in stopping the spread of disease in a flock when administered in the drinking water. The drug must be injected in clinically ill birds and is often effective in gram-negative bacterial infections. It has less nephrotoxicity than aminoglycosides. Dosage is 25 to 35 mg/kg bid or tid IM, 600 mg to 1000 mg/ gallon of drinking water.
Sulfachlorpyridazine
This bacteriostatic antimicrobial has a broad spectrum. It is very effective against E. coli and a good coccidiostat. Sulfachlorpyridazine is an excellent choice when coccidia and secondary bacterial enteritis is apparent. The dosage is 1200 mg/ gallon for 7 to 10 days.
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•.
Piperazine
This is effective only against Ascarids. The dosage is 35 mg/ kg for 2 days, 300 mg/ gallon for 2 days. Primaquine
This 8-aminoquinoline compound is used to control Hemoproteus in pigeons. It will not cure but does suppress the organism and alleviates symptoms in the patient. The dosage is 1 to 2 tablets/ gallon for 10 to 21 days before race season, then 1 to 2 days weekly. Controlling pigeon flies is probably the most important factor in controlling Hemoproteus in problem areas.
Pyrantel Pamoate
This is excellent and safe for individual dosing for Roundworms, given as 20 to 25 mg/ kg PO, 50 mg/mL liquid. Pyrethrin, Permethrin
Dusts and dips are quite effective against mites and lice. Heavy louse burdens indicate underlying causes. Dosage is liberal powdering under wings and over dorsal aspect of bird and vent area. Mix cat dip preparation containing pyrethrin and permethrin at a 50% greater dilution with 2 drops/ gallon of dishwashing detergent. Supmerge bird to neck level on a warm day. Allow no baths for a we~k ~.OSo; e.g., 2 oz. dip to 3 gallons water with 6 drops of detergent. · Lincomycin
This is a macrolide antibiotic with a similar spectrum to tylocin. It clinically is not as effective as tylocin in pigeon respiratory disease. It is often used orally in combination with spectinomycin and is useful in nasal flushes for sinus problems. The dosage is 25 to 50 mg/kg IM. Mebendazole
Mebendazole is a benzamidazole anthelmintic that is effective against most pigeon worms except cestodes. Dosage is 5 to 6 m g / kg for 3 to 5 days, 1/ 4 to 1/2 teaspoon per gallon of dog wormer preparation for 3 to 5 days.
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Metronidazole
This 5-nitro-imidazole compound is quite effective against protozoa and anaerobic bacteria, but it is not often used for flock treatment due to poor solubility. Dosage is 200 to 250 mg/kg daily for 3 to 7 days PO, 4000 mg per gallon of drinking water for 3 to 7 days. Nystatin
Candidiasis is usually secondary to prolonged antibiotic use. Nystatin is not well absorbed but may stop the replication of yeasts in the crop and lower G.I. tract. Crop stasis (sour crop) is usually due to severe lower intestinal disease. The dosage is 100,000 units per kg bid PO. Piperacillin
Its activity is similar to carbenicillin, but it is often more effective against Pseudomonas. It is the drug of choice for critically ill patients with intestinal disease. Often, piperacillin is used in combination with other antibiotics such as aminoglycosides and quinolones. It is effective in many anaerobic infections, as are other penicillins. Dosage is 100 mg/kg IM bid or tid. Enrofloxacin
This bacteriocidal quinolone chemotherapeutic agent is rapidly absorbed and penetrates body tissues well. It is excellent in respiratory infections, and it is the drug of choice for Salmonella typhimurium infections. Some adverse effects have been reported in breeding hens and squabs. It is the most likely drug to eliminate paratyphoid carrier states. Dosage is 12 to 15 mg/kg bid PO 7 to 14 days, 150 to 600 mg per gallon of drinking water for 7 to 14 days. Erythromycin
This macrolide is similar to tylocin and lincomycin. It is very irritating to muscles when injected. Dosage is 125 mg/kg tid PO, 2 to 3 g/ gallon of drinking water. Fenbendazole
Fenbendazole is a benzamidizole anthelmintic that is effective against ascarids, Capillaria, strongyles, and Tetrameres. Feather abnor-
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'· malities have been reported when it is used during the moult. The dosage is 10 to 12 mg/kg PO sid for 3 days. .,., lvermectin
This very safe and effective anthelmintic is the wormer of choice except for tapeworms and ascarids. Ivermectin is also effective for mites and lice that feed on body tissues. It is effective for feather lice when sprayed topically. The dosage is 0.5 mg to 1 mg/ kg PO or injected. Levamisole
Levamisole is very effective against ascarids and moderately effective against other nematodes. It may cause vomiting after administration. Dosage is 40 mg/kg PO once or 1000 to 1500 mg/ gallon of drinking water for 24 hours. Dimetridazole
This water-soluble 5-nitro-imidazole derivative has very good antiprotozoal activity. It is quite toxic if overdosed, causing dose-related central nervous system symptoms. The dosage is 1/ 2 to 1 tsp gallon for the (U.S. product), which is no longer available. The dosage is 1/ 4 to 1/2 tsp gallon 3 to 5 days for the Mexican or Canadian product. Doxycycline
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Doxycycline is the drug of choice for chlamydiosis. It is far superior to other tetracyclines, but it requires individual bird dosing. Dosage is 25 to 50 mg/kg PO bid. Cephalexin
Cephalexin is bacteriocidal by cell wall inhibition, similar to penicillins. It probably has little advantage over penicillins except where sensitivities indicate or when Staphylococcus is suspected. Dosage is 100 mg/ kg bid or tid PO. Chloramphenicol
. This very bro~d-spectrum bacteriostatic antibiotic reaches all body hssues well mcludmg the central nervous system. It is one of the best
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drugs for Salmonella in human medicine. Chlamydostatic properties and good gram-negative spectrum make it useful in treating conjunctivitis in respiratory conditions and eye injuries with ophthalmic drops. It is quickly excreted in the pigeon, making mean inhibitory concentrations difficult to attain. Dosage is 60 to 100 mg/kg IM tid, 250 mg/ kg PO qid, ophthalmic drops tid or qid. Chlortetracycline and Oxytetracycline
These drugs are frequently used by fanciers for respiratory disease. They are probably effective due to high incidence of chlamydia! infections in pigeons and are best used in combination with tylocin in Ornithose complex. Absorption is inhibited by the presence of calcium in the intestinal tract, so grit and layer pellets should be withheld during treatment. When offered in drinking water in warm weather, it should be freshly mixed at least twice daily. The dosage is 50 mg/kg tid or qid PO, 1000 mg to 1500 mg/ gallon of drinking water. Clazoril
This coccidiostat has the advantage of stopping oocyst shedding for prolonged periods after single tablet administration. Dosage is 5 mg/ kg PO or one 2.5 mg tablet per Racing Homer-size bird. Carnidazole
This very safe 5-nitro-imidazole antiprotozoal compound is the only drug labeled for use in pigeons in the United States. Dosage is 20 mg/ kg PO. Cefadroxil
Cefadroxil has similar activity to cephalexin but may have a longer half-life in birds. Its dosage is 100 mg/kg, bid PO. Cefataxime
This third-generation cephlosporin has an excellent gram-negative spectrum, especially against E. coli. The dosage is 100 mg/ kg IM bid or tid. Ceftidime
Although similar to cefataxime, ceftidime may be more effective against Pseudomonas. It is a possible drug of choice in pneumonia due to excellent levels in the lungs. Its dosage is 100 mg/ kg IM bid or tid.
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Aminoglycosides
Streptomycin, kanamycin and neomycin have no place, especially systemically, in pigeon medicine. Amikacin and gentamicin are useful, especially in nasal flushes and ophthalmic preparations against Pseudomonas and other difficult aerobes. They are probably quickly excreted from the pigeon's body, and their toxic properties are well known in other birds and animals, so they are seldom used systemically. They are not absorbed orally but may have some use in eliminating undesirable intestinal flora. The dosage is 1 drop qid for ophthalmic disease. Amoxicillin
Amoxicillin is well-absorbed and nontoxic in pigeons. It is recommended for many bacterial infections and is probably the drug of choice for animal bite wounds and postsurgical wound care. It is effective in some cases of salmonellosis and colibacillosis. Dosage is 100 mg/kg bid PO or 2 to 3 g / gallon of drinking water. Amoxicillin with Clavulinic Acid
This combination is nearly the same as Amoxicillin but has a much better spectrum against Staphylococcus. Probably, it has no advantages over amoxicillin unless sensitivities dictate. Dosage is 125 mg/ kg bid PO. Amprolium
This chemical ties up thiamine, inhibiting replicc;J.tidi\:""It is a very effective coccidiostat and, in the absence of clinical disease, is probably the best choice if all that is desired is to stop oocyst shedding. Dosage is 1 tsp /gallon of 20% powder, 8 mL/gallon of9.64% solution for 3-5 days. Carbenicillin
Carbenicillin is a bacteriocidal injectable w ith greater gram-negative spectrum than am oxicillin. Dosage is 100 m g / kg IM bid or tid in critically ill patients. Suggested Readings Annual Proceedings of the Association of Pigeon Veterinarians (APV). Contact the author at the address at the end of this article for information on joining the APV. Harlin RW: Pigeons. In Rosskopf WJ, Woerpel R: Petrak's Cage and Aviary Birds. Malvern, Lea & Febiger, in press
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Muller E, Schrag L: Fancy Pigeons. Hengersberg, Germany, Schober Verlags, 1985 Tudor DC Pigeon Health and Disease. Ames, lA, Iowa State University Press, 1991 Wages DP: Diseases of Pigeons. Vet Clin North Am Small Anim Pract 17:1089, 1987
Address reprint requests to Roger W. Harlin, DVM Southside Dog, Cat, and Bird Hospital 7020 South Shields Oklahoma City, OK 73149