Common diseases in broilers . There are numerous factors that contribute to diseases in chickens. Some are related to management systems, others are infectious, inherent to the bird, environmental, etc. In any case, although the etiology is different, it can be said in general that young birds are more susceptible to severe respiratory reactions because their defenses are lower because their immune system is not fully developed.
Due to the need of the poultry industry to provide protection against different avian diseases, birds, mainly broilers , are vaccinated at a very early age with live organisms against which the bird reacts by recognizing the invading agent or agents. Diseases in broilers are becoming more and more frequent. Among the most common are those listed below.
Summary
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- 1 Infectious Bronchitis
- 1Agente causal
- 2 Symptoms
- 3 Disease transmission
- 4 Treatment and control
- 2 Avian cholera
- 1Agente causal
- 2 Symptoms
- 3 Transmission
- 4 Treatment and control
- 3 Infectious coryza
- 1Agente causal
- 2 Symptoms
- 3 Disease Transmission
- 4 Treatment and control
- 4 Avian encephalomyelitis
- 1Agente causal
- 2 Symptoms
- 3 Transmission
- 4 Treatment and control
- 5 Chronic Respiratory Disease (CRD)
- 1Agente causal
- 2 Symptoms
- 3 Disease transmission
- 4 Treatment
- 6Gumboro o bursitis
- 1Agente causal
- 2 Symptoms
- 3 Transmission
- 4 Treatment
- 7 Enfermedad de marek
- 1Agente causal
- 2 Symptoms
- 3 Transmission
- 4 Treatment and control
- 8New Castle
- 1Agente causal
- 2 Symptoms
- 3 Transmission
- 4 Treatment and control
- 9 Fountains
infectious bronchitis
Causal agent
Caused by a virus (coronavirus), which only affects chickens and hens .
Symptoms
Breath sounds typical of the disease occur in both young and adult birds, including panting, rales (due to mucus from the trachea), coughing, runny nose, and watery eyes. Based on respiratory symptoms alone, it is difficult to differentiate from New Castle disease. Unlike New Castle disease, bronchitis never presents nervous symptoms and mortality is lower, egg production, although it is also affected, never drops to zero, the quality of the egg is altered for a longer time and the birds take longer to hatch. normalize posture.
disease transmission
It is easily transmitted through the air and any other mechanical means. Bronchitis usually affects a whole flock of birds simultaneously, completing its respiratory course in 10-15 days.
Treatment and control
There is no specific treatment and once it occurs it is difficult to control. Immunity can be produced quickly by applying the vaccine . The attenuated Connecticut or Massachusetts strain vaccine, alone or in combination, can be given from the first day of life.
avian cholera
Causal agent
Highly contagious disease of chickens, turkeys and other birds. It is caused by a bacteria called Pasteurella multocida .
Symptoms
It can present itself in three forms: In the acute form, avian cholera attacks the entire body, affecting large numbers of animals and causing high mortality. A large number of birds stop eating and drinking, losing weight rapidly; diarrhea may occurgreenish-yellow in color and a marked drop in egg production. Paralysis may occur due to swelling of the feet and toes. In the peracute form, it causes sudden death in apparently healthy animals. The attack is so rapid that the farmer himself may not realize that he is facing an outbreak of the disease. Sometimes it can take the chronic form, in which the disease is localized, causing inflammation on the face and chins of the hens. Chins may take on a wine-red color and feel hot to the touch. Cholera does not usually occur in young chickens, but it does occur in turkeys.
Transmission
Physical waste from sick birds contaminates feed , water , and litter, thus infecting other healthy animals. They can also become infected when healthy birds peck at the carcasses of animals that have had the disease. The outbreak occurs between four and nine days after infection.
Treatment and control
For its treatment, the use of sulfas, such as sulfaquinoxaline, has been recommended. Other products such as enrofloxacin and fosfomycin are recommended for the treatment of this and other respiratory diseases. To control the disease, it is recommended to eliminate the carcasses soon, so that they are not consumed (cannibalism) by other birds. A complete cleaning and disinfection of the facilities and equipment must be carried out. Bacterin application is advisable in most areas where there is a high degree of risk of an outbreak.
infectious coryza
Causal agent
This disease is caused by a bacterium called Haemophilus gallinarum .
Symptoms
The first symptoms include sneezing, followed by a foul-smelling discharge and swelling of the eyes and sinuses. As the disease progresses, the exudate becomes cheesy (like cheese) and accumulates in the eyes; producing swelling and in many cases even the loss of the eyes. The problem can be accelerated or aggravated when there are sudden changes in air currents, temperature, humidity, or due to deworming and vaccination. Generally decreases feed intake and egg production .
transmission disease
It can be transmitted from one animal to another and from one flock to another by direct contact, by means of dust particles that move in the air between sheds, or by people who care for the animals.
Treatment and control
The best control is through prevention, raising new batches of chicks in houses away from old birds or those suspected of being carriers of the disease. There is no specific treatment, although the use of antibiotics is recommended to avoid possible secondary infections. Antibiotics such as streptomycin can be applied intramuscularly in a single dose of 200 milligrams per pullet or hen, or 300 to 400 milligrams per rooster. Erythromycin in drinking water at 0.5 g/gallon (3.785 l) for seven days, or in feed at 92.5 g/ton for 7 to 14 days.
avian encephalomyelitis
Causal agent
The disease is caused by an “enterovirus” from the picornavirus group. It generally affects birds between the first and third week of age and adults during the laying period.
Symptoms
Symptoms occur more frequently in young animals, manifesting a hesitant walk, incoordination and even partial or total paralysis. As muscle incoordination increases, birds tend to sit on their tarsi (heels), worsening until they can no longer walk. When handling these birds, rapid body tremors can be felt.
Transmission
Encephalomyelitis is transmitted primarily through the eggs of infected birds ; although the possibility of spreading directly or through feces is not ruled out.
Treatment and control
There is no curative treatment and the sacrifice of affected young animals is recommended. Breeders vaccinated after 10 weeks of age transmit immunity to offspring via the egg.
Chronic respiratory disease (CRD)
Causal agent
Mainly caused by Mycoplasma gallisepticum , although Escherichia coli has also been found.
Symptoms
The first symptoms resemble those produced by New Castle disease and infectious bronchitis, such as difficulty breathing, runny nose, and tracheal rales. A whitish foamy material is often found in the trachea and air sacs. In advanced cases of the disease, the liver and heart can be seen covered by a white or yellow exudate. The course of the disease is slow.
disease transmission
It is transmitted by direct contact, from one bird to another or through dust particles carried by the wind from one shed to another. The main problem is that chickens can transmit the disease to their children through the egg.
Treatment
Although treatment with specific antibiotics gives satisfactory results, economically speaking, it is best to control it by eliminating sick animals. Serological tests allow positive breeders to be detected at the farm level, with which birds free of this disease can be offered. Fertile eggs could be treated with antibiotics such as tylosin tartrate to kill M. gallisepticum organisms. Erythromycin glutamate at concentrations of 2 g/gallon of water for three days has markedly reduced infection. Tylosin tartrate is used with very good results in doses of 0.5 g/l of water, for 2-3 days, depending on the infection.
Gumboro o bursitis
Chicken with “Gumboro or bursiti”
Causal agent
This disease is caused by a birnavirus, which is highly resistant to unfavorable environmental conditions, making it difficult to eradicate from infected farms.
Symptoms
The first symptom of Gumboro disease or Bursitis is a breath noise. Other symptoms that can be seen are decay, ruffled feathers, tremors, watery diarrhea and prostration. Outbreaks most often occur when birds are 3 to 8 weeks old. Mortality generally does not exceed 10% and in a second infection of the same batch, mortality is even lower. The Bag of Fabricius(located above the cloaca), it will be swollen and its size may be two or more times its normal size. In healthy animals, the Bursa of Fabricius is smaller than the gallbladder. In chronic cases, the bursa will be smaller (atrophies), so the response to vaccination is lower, increasing susceptibility to other infections.
Transmission
The disease is very contagious and is transmitted by direct contact with birds, their droppings; or through the equipment and clothing of the operators.
Treatment
An adequate treatment is not yet known. Prevention, of breeders and young birds, through vaccination is the best control of the disease. The most effective method to control Gumboro disease is to induce high immunity in mothers, which is transmitted to their offspring through the egg.
Mark’s disease
Causal agent
The disease is caused by a herpes virus.
Symptoms
It rarely happens that some animals die without presenting the characteristic symptoms of the disease; however, in most cases the condition occurs in the sciatic nerves , causing some degree of paralysis of the legs and wings. In advanced cases, fallen animals are seen with one leg stretched forward and the other backward, and one of the wings drooping, as if trying to lean on it. As part of the leukosis complex, tumors can also be seen in the liver, lungs, kidneys, ovaries, eyes, and other organs.
Due to the paralysis of the legs, the animals cannot move to the feeders and drinkers, so they gradually lose weight until prostrated on the ground, they die of starvation. The muscles of the breast are reduced almost completely, feeling the bone of the sternum or keel without meat. Symptoms generally appear after 15 weeks of age; mortality being greater than 50% in batches of unvaccinated birds.
Transmission
The transmission of the virus is carried out mainly through the scales that are shed from the follicles (root) of the feathers, which are transported by the wind. These scales adhere to dust particles that accumulate on the walls and sieves of chicken coops, where they can survive for more than a year in these conditions. Hence the importance of sanitation in the facilities, so the sieves should be shaken frequently.
Treatment and control
Until today there is no known treatment against Marek ‘s Disease . Its control is carried out by vaccinating all animals, subcutaneously in doses of 0.2 ml, during the first 24 hours of life. This vaccine will protect birds throughout their lives. The vaccine must be applied to newly hatched birds before they leave the hatchery.
New Castle
Chickens with New Castle disease
Causal agent
New Castle disease is caused by a paramyxovirus. Although only one serotype of the virus is known, different strains have been isolated, which are classified according to their virulence or the speed with which they can kill the embryo. The “lentogenic” strain (La Sota) is the one that takes the longest to kill the embryo, the “mesogenic” (B1 and Roakin) is the intermediate strain, and the “velogenic” (Kansas) strain is the most pathogenic and takes less time to kill the embryo. Currently, the country is free of this disease and was thus declared by the Department of Agriculture of the United States of America (USDA).
Symptoms
The first symptoms are respiratory problems with cough, wheezing, rales of the trachea and a hoarse chirp, followed later by the characteristic nervous symptoms of this disease; in which birds place their heads between their legs or back between their shoulders, moving their heads and necks in circles and walking backwards. Mortality can be greater than 50% in young animals, in layers, although it is not so high, respiratory symptoms appear and egg production drops to zero in one or two days. Production recovers about six weeks later, but you will find eggs with thin and misshapen shells, and some even without shells. In animals affected with New Castle, a greenish diarrhea can sometimes be observed, indicating a lack of food intake.
Transmission
This disease is highly contagious and is spread through the nasal discharge and droppings of infected birds.
Treatment and control
There is no effective treatment for New Castle disease. The only control is achieved by vaccination, which is repeated several times during the life of the animal. As a general rule, the first vaccination is recommended four days after birth with the mild strain B1, then it is continued at four and twelve weeks with the La Sota strain. From now on, he will be vaccinated every three months with the La Sota Strain. For ease of application, when there are large batches of birds, it is recommended to do it through drinking water, in sufficient quantity so that they can consume it in about 15-20 minutes. Nonfat dry milk should be added to the water as a stabilizer at the rate of one tablespoon per gallon.
