Detailed Explanation of Diagnosis and Prevention Methods for Common Chicken Diseases
Pathological necropsy, as a basic means of disease diagnosis, is widely used in production because of its rapid diagnosis and ease of operation. However, since there are many kinds of chicken diseases and different diseases often show similar lesions, whether they can be correctly identified is the basis for making a correct clinical diagnosis. The following discussion is provided on the identification of common lesions in production for reference.
Edema sites are mostly seen in the chest, abdomen and inner sides of both legs, and the exudate is mainly gelatinous.
The exudate is yellow-green or blue-green in color, which indicates Pseudomonas aeruginosa infection and selenium-vitamin E deficiency.
The exudate is yellow-white in color, which indicates fowl cholera.
The exudate is blue-purple in color, which indicates staphylococcosis.
Hemorrhage is petechial or patchy.
Common diseases include infectious bursal disease, fowl cholera and staphylococcosis.
In addition, muscle hemorrhage can also be seen in vitamin K deficiency, sulfonamide poisoning, aflatoxin poisoning, inclusion body hepatitis and leucocytozoonosis.
Tracheal and laryngeal diseases often involve mucosal congestion and hemorrhage, with mucus and other exudates in the trachea and larynx. These lesions are mainly seen in respiratory system diseases.
Mucosal congestion with exudate in the trachea indicates infectious bronchitis lesions.
Diffuse hemorrhage of the laryngeal and tracheal mucosa with bloody mucus inside indicates infectious laryngotracheitis lesions.
Petechial hemorrhage on the mucosal rings of the trachea indicates Newcastle disease lesions.
Mucus exudate and other lesions in the respiratory tract can also be seen in mycoplasmosis and infectious coryza.
Diseases causing necrotic spots or necrotic foci in the liver include fowl cholera, pullorum disease, typhoid, acute colibacillosis, Pseudomonas aeruginosa infection, spirochetosis, olaquindox poisoning and mequindox poisoning. Diseases causing grayish-white nodules in the liver include Marek's disease, avian tuberculosis, pullorum disease, leukemia, chronic aflatoxin poisoning and leucocytozoonosis.
Intestinal hemorrhage is a symptom common to the acute stage of many diseases, such as Newcastle disease, infectious bursal disease, fowl cholera, staphylococcosis, streptococcosis, necrotic enteritis, Pseudomonas aeruginosa infection, coccidiosis, avian influenza and poisoning.
Cecal lesions mainly consist of caseous material blocking the ceca; the diseases indicated by such lesions include cecal coccidiosis, histomoniasis, paratyphoid and pullorum disease.
In Newcastle disease, hemorrhage can be seen on the mucosal papillae or between the papillae; in infectious bursal disease and spirochetosis, hemorrhage of the mucosa at the junction of the gizzard and proventriculus is more commonly seen.
Diseases causing hemorrhage of the proventricular mucosa also include olaquindox poisoning, mequindox poisoning, sulfonamide poisoning, avian influenza and inclusion body hepatitis.
Diseases causing renal dysfunction can all lead to urate deposition in the ureters, such as gout, infectious bursal disease, vitamin A deficiency, infectious bronchitis, pullorum disease, spirochetosis and long-term excessive use of drugs.
Common diseases include ascites, colibacillosis, aflatoxin poisoning, selenium-vitamin E deficiency, pullorum disease, paratyphoid and yolk peritonitis.
These lesions are mainly seen in colibacillosis granuloma, Marek's disease, pullorum disease, typhoid and sulfonamide poisoning.
They are mainly seen in chicken colibacillosis, yolk peritonitis, pullorum disease, typhoid, fowl cholera, histomoniasis and mycoplasmosis.
The above are only some common lesions in clinical practice. Clinically, due to the influence of the nature of the disease, the use of vaccines or drugs and other conditions, the symptoms of the same disease also change under different conditions, and some flocks may have complex situations of concurrent or secondary diseases. Therefore, during clinical diagnosis, pathological necropsy changes should be analyzed dialectically. The lesions of affected chickens do not exist in isolation; it is necessary to grasp the key lesions, integrate the overall necropsy changes, and at the same time combine flock feeding management, epidemiology and clinical symptoms for comprehensive analysis, so as to make a correct clinical diagnosis and thereby provide a scientific basis for disease control.
Newcastle Disease
Newcastle disease is an acute septicemic disease caused by a virus. It occurs mostly in spring and autumn, spreads quickly and has a high mortality rate.
The incubation period of this disease is 3-5 days. It is divided into three types: peracute, acute and chronic. Generally, in the early stage of an epidemic, it mostly occurs in the acute form.
[Main symptoms] Elevated body temperature (43-44°c), closed eyes, ruffled feathers, neck retraction, drooping wings, unsteady gait or circling; dark purple comb, mucus flowing from the mouth, head shaking, gasping, making "cluck, cluck" sounds, difficulty breathing, green or yellow droppings; in the later stage, paralysis of the legs and wings, with high mortality.
[Prevention] The most reliable method is vaccination for disease prevention.
1. Preventive vaccination: For chicks aged 1-2 weeks, dilute Newcastle disease vaccine strain II 10 times and administer by nasal drops; repeat once after about 0 days; for medium and large chickens over 2 months of age, dilute strain I vaccine 1000 times and inject 1 milliliter intramuscularly per chicken, which can provide immunity for one year.
2. Drinking water immunization method: Dilute Newcastle disease vaccine strain III (f strain) into a 0.1-0.3% aqueous solution and let the chickens drink freely; give it once more after 10-30 days, which can provide immunity for 7 months.
3. Strictly blockade the epidemic area and carry out thorough disinfection.
[Treatment]
At present, there is no specific drug treatment for this disease. The following may be tried:
1. 3-5 cloves of garlic, crushed and mixed with a small amount of sulfur powder and raw oil, administered orally, twice daily.
2. Half a croton seed, crushed (sold in pharmacies, toxic, strictly control the dosage), mixed with a small amount of raw oil and administered orally, twice daily.
3. Dilute Newcastle disease vaccine strain I 500 times and inject 1 milliliter intramuscularly per sick chicken, which has a certain therapeutic effect. According to data, for sick chickens that already have neurological symptoms, they generally recover 2-3 days after injection.
Fowl Cholera
Fowl cholera is a severe infectious disease, generally occurring in sporadic endemic form. It can occur in all four seasons, sometimes spreads faster than Newcastle disease, and often causes sudden death without any symptoms. This disease can also infect ducks, geese and rabbits at the same time.
[Prevention] Inject fowl cholera vaccine regularly every year. For chickens over 2 months of age, regardless of size, inject 2 milliliters intramuscularly (or subcutaneously) per chicken, with vaccination once every 4-6 months; adding 0.01% potassium permanganate (gray manganese oxide) or 0.2% sulfadimidine sodium aqueous solution to drinking water can also have a certain preventive effect.
[Treatment]
1. Penicillin 30,000-50,000 international units per chicken, administered by intramuscular injection, 3 times daily.
2. Sulfathiazole sodium or sulfadiazine sodium by intramuscular injection, 1 gram per chicken each time (each tablet contains 250 milligrams), 2-3 times daily.
The above drugs have definite efficacy, but after the chicken's comb turns black-purple, the cure rate is relatively low.
Pullorum Disease
Pullorum disease is a bacterial infectious disease. Both large and small chickens can be affected, but it is more commonly seen in chicks around half a month old, with a relatively high mortality rate.
Affected chicks are listless, with retracted heads, drooping wings, and white pasty watery droppings. The anus is often stuck shut by feces, and they make "cheep, cheep" sounds when defecating. Adult chickens are mostly latent carriers; only in severe cases are anemia and diarrhea seen, and laying hens show a marked decrease in egg production.
[Treatment]
1. Add 200-400 milligrams of furazolidone per kilogram of feed (that is, 2-4 tablets), mix well and feed to chickens for 7 consecutive days, stop for 3 days, then feed again for 7 days.
2. Administer oxytetracycline (or chlortetracycline or tetracycline) at 200 milligrams per kilogram of chicken body weight (each tablet contains 250 milligrams); or add 2-3 grams of oxytetracycline per kilogram of feed (that is, 8-12 tablets), mix well and feed to chickens for 3-4 days.
3. Feed each chicken 2000 international units of penicillin mixed into the feed daily for 7 consecutive days.
4. Add 10 grams of sulfaguanidine (or sulfadiazine) per kilogram of feed (that is, 20 tablets) or 5 grams of sulfadimidine (that is, 10 tablets), mix into the feed and feed to chickens for 5 consecutive days; streptomycin or chloramphenicol can also be added to drinking water at 0.1-0.2% to feed the chickens for 7 consecutive days.
The above drugs are best used alternately to help improve the therapeutic effect.
Mycoplasma Disease of Chickens (Chronic Respiratory Disease)
[Symptoms] Respiratory rales appear (more easily heard at night), runny nose, coughing and sneezing; poor appetite and weight loss. In the later stage, swelling of the eyelids is common, with the eyes protruding like tumors, the eyeballs compressed and atrophied, causing blindness; the course of disease lasts from one month to several months.
[Prevention] Disinfect regularly and maintain good hygiene in the chicken house; administer 2000 units of streptomycin by nasal drops to each newly hatched chick.
[Treatment]
1. Streptomycin: 90,000 units for small chickens, 100,000 units for medium chickens and 200,000 units for large chickens by intramuscular injection, 3 times daily for 3-5 consecutive days.
2. Add 400-800 milligrams of oxytetracycline or tetracycline per kilogram of feed (each tablet contains 250 milligrams), mix well and feed to chickens.
3. Tylosin has a special effect on mycoplasma disease. Add 125-250 milligrams of tylosin to 1000 milliliters of water as an aqueous solution for chickens to drink.
Coccidiosis of Chickens
Coccidiosis of chickens is a relatively serious and common disease harming chicks. Chickens aged 15-25 days are most susceptible, and both morbidity and mortality are high; the incidence is highest in the rainy season, and once the disease occurs it can cause widespread prevalence. When adult chickens are infected with coccidiosis, the symptoms are somewhat milder and death is rare.
[Symptoms] Affected chicks first show general weakness, listlessness, a tendency to huddle together, drooping wings, ruffled feathers and tightly closed eyes, and they tend to sleep; diarrhea with brownish-red bloody watery droppings; pale comb and wattles, drinking large amounts of water, then stopping eating, and finally becoming extremely emaciated.
[Prevention]
1. Keep the chicken house sanitary and dry, and disinfect regularly.
2. Isolate sick chickens promptly and treat them.
3. Add 150-250 milligrams of furazolidone per kilogram of feed (each tablet contains 100 milligrams), mix well and feed to chickens for 7 consecutive days, stop the drug for 3 days, then use it again for 5-7 days.
[Treatment]
1. Calculate 3000-6000 units of penicillin per chicken, dissolve the penicillin in water, then use half of the solution to mix with powdered feed for feeding, and pour the other half into a drinker to replace drinking water, allowing the chickens to drink freely.
2. Administer 2-4 milligrams of oxytetracycline or chlortetracycline per chick daily (each tablet contains 250 milligrams) for 3 consecutive days; or add 800 milligrams of chlortetracycline per kilogram of feed, mix well and feed to chickens.
3. Add 250 milligrams of furazolidone per kilogram of feed (that is, 2.5 tablets), mix well and feed, or add the same dose to drinking water for chickens to drink, for 2-3 consecutive days.
Fowl Pox
Fowl pox is a highly contagious disease. Affected chickens grow slowly and may even die.
The incubation period of this disease is 4-8 days. It is divided into two types: the skin form and the diphtheritic form.
[Prevention]
1. Immunization with pox vaccine is suitable for chickens of all ages over 7 days old. At the time of use, dilute 10-50 times with saline or cool boiled water, dip a pen nib (or a large needle tip) into the vaccine and prick it into the subcutaneous tissue at the non-vascular area on the inner side of the chicken's wing. About 7 days after vaccination, the pricked site becomes red, swollen and blistered, then gradually dries, forms a scab and falls off, providing immunity for 5 months.
2. Maintain environmental hygiene and eliminate mosquitoes and chicken lice.
3. Isolate sick chickens promptly, or even cull them, and thoroughly disinfect the site and equipment.
[Treatment] At present there is no specific drug treatment; symptomatic treatment is generally used.
Ascaridiasis
Ascaridiasis is a common parasitic disease of chickens.
[Prevention] Deworm regularly 3-4 times a year.
[Treatment]
1. Administer 0.15-0.25 grams of piperazine per kilogram of chicken body weight (each tablet contains 0.5 grams) orally; or grind the drug finely and mix it into the feed, feeding it once in the evening.
2. Use 20-30 milligrams of tetramisole per kilogram of chicken body weight (each tablet contains 25 milligrams), mix into the feed and administer.
3. Use 1-2 milliliters of gasoline for crop injection.