When heated or overheated, it shows an acute course. Symptoms are accelerated breathing, mouth breathing, dyspnea, elevated body temperature and increased appetite several times; Congestion of conjunctival vein, incomplete or complete paralysis of feet and wings, muscle spasm of trunk and neck. Autopsy showed meningeal congestion and punctate bleeding; Brain congestion and edema, accompanied by different degrees of bleeding.
Before and during the onset of such diseases, the room temperature of the brooding room (including the thermal umbrella) is often too low or too high.
2. Chickens with pullorum disease are characterized by mental fatigue, anorexia, drooping wings and occasional dyspnea; Frequent diarrhea, multiple rows of white thin feces, and villi near cloaca are adhered by excrement. Autopsy showed that the absorption of yolk was delayed, and there were necrotic foci or nodules in myocardium, lung, intestine and myostomach. Some have pericarditis, a little bleeding and focal necrosis in the liver, and occasional urate filling in the kidneys and ureters. The disease often occurs in a large number of chicks aged 2 ~ 3 weeks.
Pathogens can be easily separated from the nodules of internal organs such as liver, lung and heart.
Third, paratyphoid chicks are often acute, mostly occurring in chicks within 2 weeks old. Its symptoms are sudden onset, dysentery and feces around cloaca; Serous suppurative conjunctivitis, eyes half closed or completely closed; Sometimes it is difficult to breathe, and sometimes there are neurological symptoms such as paralysis and convulsions. The main lesions are in the liver and intestine: hepatomegaly, blunt edge, cellulose membrane on the capsule, and small gray-yellow necrosis focus in the liver parenchyma; Small intestinal mucosal edema, local congestion, often accompanied by punctate bleeding. Salmonella can be isolated from liver and other internal organs.
Fourth, chronic respiratory diseases (mycoplasma diseases) are often infected in large numbers. The characteristic symptoms are mucus nose, cough and sneezing, which are more obvious at night, and there are tracheal rales and mouth breathing in the later stage; Generally, the course of disease is long, about 1 ~ 2 months or longer. Autopsy found sinus, trachea and balloon lesions. The mucosa of infraorbital sinus is edema, congestion and bleeding, and the sinus cavity contains transparent or turbid mucus; Catarrhal exudates in nasal cavity, trachea and trachea; The balloon wall is thickened with a small amount of yellow-white granular exudate or cellulose exudate; A few cases also have pneumonia. When there is secondary bacterial invasion or vitamin A deficiency, the symptoms of ophthalmia are also obvious. Healthy chickens were inoculated with respiratory secretions from sick chickens, and the incubation period was 4 ~ 2 1 day, while turkeys could be artificially infected, and the incubation period was 2 ~ 17 days, showing sinusitis-induced swelling.
Five, aspergillosis, also known as nanny pneumonia, is more common in the rainy season. The feed, padding and trough are moldy, and under the insulation umbrella, a large number of mold spores are easy to float in the air, which makes chicks susceptible to infection. Sick chickens have difficulty breathing, the number of breaths increases, the mouth opens to breathe, the neck airbag expands obviously when inhaling, and it creaks when exhaling, especially at night. Autopsy found that there were small yellow-white nodules in the lungs and airbags, and sometimes gray-yellow or green or even black fungal hyphae were visible to the naked eye, especially in the trachea, airbags and lung tissue. In addition to lungs and air sacs, this nodule can also be found in pleura, abdominal cavity and mesentery. Microscopic examination of pathological tissue can generally find mold spores and hyphae, but sometimes it is necessary to check multiple pieces to find them.
Six, the symptoms of infectious bronchitis are runny nose, cough, dyspnea and tracheal rales, eyelid and sinus swelling. Autopsy found that there were viscous secretions in the bronchus, sometimes mixed with bean curd residue-like secretions, nasal cavity and sinus mucosa were congested and filled with viscous secretions, and there were also viscous or cellulose-like secretions on the wall of the airbag. The disease is often infected in groups, and the mortality rate of chicks can be as high as 25%, while the mortality rate of chickens over 6 weeks old is very low.
After healthy chicks were inoculated with respiratory secretions from sick chickens, tracheal rales appeared within18 ~ 36 hours.
Seven, protein and chicks lacking in essential amino acids are stagnant in growth and development, and they are afraid of cold, and their body temperature often drops below 40℃, resulting in a large number of deaths. Autopsy showed that the body was thin, the muscles were usually pale and atrophied, the blood was thin, the color faded and the coagulation was slow. Fat tissues such as coronary sulcus and subcutaneous tissue disappeared, showing colloid infiltration, often accompanied by abdominal cavity, pericardial edema and ascites.
Analysis of the feeding situation some time ago shows that there is a process of protein and essential amino acid deficiency.
Eight, salt poisoning feed salt content of 3% or 4 grams per kilogram of body weight, can cause salt poisoning. Sick chickens show extreme excitement, increased breathing and pulse frequency, dyskinesia, weakness of feet, difficulty in walking and even paralysis; Crops swell, thick secretions flow out of the mouth and nose, and thirst is extremely increased; Late diarrhea, feathers around the anus are stained by feces. Autopsy showed that the crop was filled with viscous liquid, the glandular gastric mucosa was congested, and the duodenum and the anterior segment of the small intestine were obviously congested or bleeding. Common subcutaneous tissue and pulmonary edema, ascites in abdominal cavity and pericardium, and a little bleeding in the heart.
Vitamin A deficiency at 9 or 2 weeks old, growth retardation, weakness at 3 weeks old, dyskinesia, unkempt feathers, inflammation of eyes and nose, swelling of eyelids, bean curd residue under eyelids, secretion adhesion between upper and lower eyelids, and secretion in nasal cavity; Dry eye, corneal perforation and eyeball subsidence are long-term processes. Autopsy found small white pustules or ulcers in the nasal cavity, mouth, esophagus and pharynx; The kidney is gray and swollen, and there are small tubes criss-crossing on the surface, interwoven into a net and filled with white contents. This is the deposition of urate. In severe cases, white urate deposits were also found in the heart, pericardium, liver, spleen, chest cavity and abdominal cavity.
Investigation and analysis of the feeding situation some time ago will reveal the lack of vitamin A in the feed.
Ten, vitamin D deficiency in addition to the growth and development is blocked, see sick chicks leg weakness, mouth and claws soft and easy to bend, difficult to move, swing from side to side, after a few steps of migration, often squat to rest. Autopsy showed that the joint between ribs and spine was spherical swelling, the ribs lost their normal hardness, and the thoracic corridor at the joint between ribs and vertebrae was sunken.
Some time ago, the investigation and analysis of feeding situation found that there was a lack of vitamin D or light.
Eleven, coccidiosis coccidiosis mainly occurs in chicks aged 20 ~ 45 days. The sick chicks are depressed, with loose feathers and dyskinesia; Diarrhea, the feces are brownish red or white, and the feathers around the cloaca are stained by this kind of feces. The changes of autopsy are mainly in the intestine, and the severity and location of intestinal lesions are related to the species of coccidia: cecal coccidia mainly invade the cecum, showing obvious swelling and congestion of the cecum and thickening of the cecum epithelium; Other coccidia mainly invade the small intestine, and small punctate lesions or nodules or even ulcers appear in the intestinal mucosa; Sometimes edema and thickening of the intestinal wall can be seen, and there is bloody exudate on the mucosal surface. Intestinal contents are often white paste, because coccidia damage the secretion function of intestinal mucosa and glands, and white paste is undigested powder. Stool examination showed coccidia cysts.
Twelve, chickenpox skin acne often occurs in the crown, meat, mouth, eyelids and other parts with less feathers. Acne rash begins with small gray spots, gradually develops into small papules, and then increases continuously, merging into large and thick scabs. The symptoms of rhinitis appear in the early stage of mucosal varicella. Nasal fluid is serous at first, and then it can become mucinous and purulent. If it spreads to the suborbital sinus and conjunctiva, the face will swell, and the conjunctiva will be filled with purulent or cellulosic exudates, which may even cause keratitis and even blindness. When pseudomembranous lesions appear in the mucosa of mouth, pharynx and larynx, it is called chicken diphtheria.
According to the epidemic situation of chickenpox and its characteristic symptoms and lesions, chickenpox can be diagnosed clearly.
Thirteen, Newcastle disease or avian influenza Generally speaking, in the case of natural infection, the incidence of this disease in chicks is less than that of adults. Acute attacks often involve the whole population, and the mortality rate can reach 100%. At the beginning of the disease, the body temperature rises, and the eyes are half closed or completely closed, showing a lethargic state; Diarrhea, thin feces, yellow-green or yellow-white, sometimes mixed with blood; Because of fever, I drank too much water, which led to water accumulation in crops; Nose and mouth secretions increase, often flowing out of the mouth, gurgling in the throat, and breathing with the mouth open is common; In the later stage of the disease, neurological symptoms often appear. Autopsy showed glandular stomach bleeding and ulcer, and catarrhal inflammation was found in the whole intestinal mucosa, especially at the junction of duodenum, posterior segment of large intestine and small intestine to cecum. There are also cellulous necrotic lesions in intestinal mucosa, which are scattered in small spots and chaff-like, cloacal mucosal bleeding, cellulous necrotic inflammation and ulcers.
Microscopic examination with pathological tissue smear showed that no bacteria could be seen.
There are many typical characteristics of Newcastle disease and avian influenza in chickens. According to the mass epidemic situation and characteristic symptoms and lesions, preliminary diagnosis can be made, such as pathogen identification and serological detection, which will make the diagnosis more accurate.
Fourteen, the most common manifestation of pecking addiction is plucking addiction, and the tail or body feathers of chickens are bare; Sometimes I see the blood vessels on my feet, which leads to bleeding and limping; After severe pecking injury in anus, resulting in traumatic bleeding, chickens attacked, the abdominal wall was pecked through, the intestine was pulled out, and the internal organs and muscles were pecked through.
This is because the chicken's diet is not perfect, and the lack of some nutrients such as protein, vitamins or minerals may lead to pecking addiction. Poor feeding management, different age and physical strength of chickens, or laying the ground with inedible fillers can also cause such adverse consequences.
Fifteen, infectious bursal disease generally occurs in 2 ~ 4 weeks old, depressed, white feces, death peak. Autopsy showed leg muscle bleeding, myogastric subcorneal or glandular nipple bleeding, most bursa of Fabricius swelling, congestion or bleeding, and sometimes bursa of Fabricius atrophy.
Sixteen, infectious encephalomyelitis is generally found in chickens under the age of 1 month, only nervous system symptoms, paralysis, head and neck or systemic tremor, failure and death. There was no obvious damage to the naked eye at autopsy.