Porcine asthma is also known as swine local epidemic pneumonia or Mycoplasma hyopneum (mycoplasma) pneumonia. It is a respiratory contact infection caused by Mycoplasma pneumoniae (mycoplasma). The long-term growth and development of sick pigs, low feed conversion rate, and generally low mortality, but secondary infections and initial outbreaks can also cause serious deaths, resulting in great economic losses, bringing to the development of the pig industry. Serious harm. The disease was discovered in Ningbo in 1955 and still exists today.
1. Pathogens.
Mycoplasma hyopneum (mycoplasma) has no cell wall and is a polymorphic microorganism. The resistance to the outside world is weak, and the virulence is lost in less than 36 hours after being discharged from the body. Commonly used disinfectants can achieve the purpose of disinfection.
2. Popular characteristics.
Pigs of different ages and breeds can be infected, but suckling pigs and weaned piglets are more susceptible, with higher morbidity and mortality. Sows and adult pigs are mostly chronic and recessive. Sick and carrier pigs are the source of infection. The mycoplasma is present in the lungs and nasal fluid of sick pigs, and is excreted by coughing and asthma, and is transmitted through the airflow. The disease generally has no obvious seasonality, but it is more common in the cold and hot and cold seasons. If the feeding management is not good, it is too crowded, and the pig house is damp, it will reduce the resistance and make the disease prone to occur.
3. Clinical symptoms.
The incubation period is generally 11 to 16 days, and the shortest incubation period is 3 to 5 days, and the longest period is up to 1 month. The main symptoms are cough and asthma. The body temperature did not change much, and the appetite was normal at the beginning of the disease. The number of coughs continues to increase, especially in the morning and after intense exercise and during feeding, a continuous cough occurs. As the disease progresses, breathing difficulties occur, manifesting as obvious abdominal breathing, which is severely gasping. This is the pig's mental spirit is very poor, the appetite is reduced, the body is getting thinner, the fur is rough, the back of the bow is walking, the walking is slow, and the body is cold. The general course of disease is long, and most of them are delayed for more than 2 to 3 months. Often due to reduced resistance and concurrent pig disease. In new sows, pregnant and lactating sows, acute asthma is often prone to occur. A small number of sick pigs have a slightly elevated body temperature, and the course of disease is about 7 days, often due to exhaustion and asphyxia.
4. Pathological changes.
The main lesion is seen only in the lungs. Acute death sees the lungs with varying degrees of edema and emphysema. In the heart, the tip of the leaf, the middle leaf and some cases of the temporal lobe, there is a bronchitis, the heart leaf is most prominent. The color of the lesion is like a fresh muscle, commonly known as meat. As the disease progresses or the condition worsens, the color of the lesion becomes light red or grayish white, commonly known as pancreas or shrimp. The boundary between the lesion and the normal lung tissue is clear. There was no significant change in other internal organs.
5. Diagnostic points.
According to epidemiology, clinical symptoms and lesion characteristics can be diagnosed. However, when there are only a few cases in the early stage of the epidemic, attention should be paid to the differences between influenza and swine plague. Porcine influenza is an infectious disease that suddenly bursts out and spreads rapidly. Most pigs in the herd can develop symptoms within 2 to 3 days. The sick pig's temperature rises and does not eat, but it recovers quickly and the mortality rate is low. Most pigs quickly stop after a week of onset. Porcine pneumonia is sporadic or local epidemic, clinical symptoms are elevated body temperature, and appetite is abolished. The course of disease is 1 to 2 days. The main lesions were sepsis or fibrinous pneumonia. The blood or liver smears of the pigs were taken from the pigs. The stained microscopic examination showed two highly concentrated Pasteurella multocida.
6. Control measures.
(1) Prevention. Non-infected areas and pig farms should adhere to the principle of self-supporting and self-supporting, and try not to introduce pigs from other places. If they must be introduced, they must be strictly isolated and quarantined; strengthen feeding management, do veterinary health work, promote artificial insemination, avoid breeding, Sows are in direct contact to protect healthy sows. In the epidemic areas, pig farm management should be strengthened to enhance the resistance of pigs; sows are kept in a single circle and are not arbitrarily mobilized; piglets are kept in nests, do not mix casually, and promote the early recovery of sick sows, which can greatly reduce piglets. The incidence rate; the use of regular X-ray fluoroscopy and other quarantine methods to remove sick pigs and suspected sick pigs, and gradually expand the health of the herd.
(2) Treatment. 1 oxytetracycline treatment is good. The dose is 30-40 mg per kilogram of body weight, intramuscularly, once a day, for 3 to 5 days. The condition is mild, and generally strengthening the management of feeding can promote rehabilitation. In pigs that are severely ill or have stopped eating, the symptoms can be significantly improved after treatment with oxytetracycline. 2 kanamycin. Piglets are 4 to 50,000 units per kilogram of body weight, 2 to 30,000 units of large pigs, intramuscularly, once a day, 3 to 5 days for a course of treatment. The interval between each treatment is 7 to 10 days, generally 1 to 2 courses of mild illness, and 3 to 4 courses of severe illness.
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