How to Prevent and Control Common Diseases in Pigs in Winter and Spring

This disease is an infectious disease of piglets caused by Salmonella. Piglets aged 1-4 months have high morbidity and mortality rates. The disease occurs in endemic or sporadic form, often in cold, changeable weather and rainy seasons. Poor environmental hygiene and reduced resistance of piglets can induce this disease.

Symptoms and lesions: In the initial acute onset, it is similar to swine fever and requires comprehensive judgment combined with other examinations. The typical symptom is persistent diarrhea with a chronic course, and some piglets also show pneumonia symptoms. Lesions: Acute cases often die of shock, with purple congestion at the extremities and systemic septicemia changes - hemorrhage of serous membranes and mucosa. Chronic cases commonly show typical necrosis and ulcers in the colonic mucosa, or diffuse necrosis of the mucosa; the intestinal wall thickens and loses elasticity; the liver shows small focal necrosis.

Diagnosis and prevention: Acute cases can be confirmed by isolating the pathogenic bacteria from parenchymal organs, while chronic cases should be confirmed by combining with laboratory diagnosis. Prevention is the main approach for this disease, with attention to improving feeding management and sanitary conditions. In endemic areas, suckling piglets over 1 month old and weaned piglets should be immunized by injection with attenuated vaccine, according to the instructions. After onset, furazolidone or sulfonamide drugs can be selected, administered twice daily for 3-5 consecutive days. The pens should also be thoroughly cleaned and disinfected.

Swine Enzootic Pneumonia

This disease is a chronic respiratory disease of pigs caused by Mycoplasma hyopneumoniae. Pigs of different breeds, ages and sexes can all be infected. Southern pigs and imported pigs raised in the north are highly susceptible to the disease. It occurs more frequently in cold, humid conditions and when the climate changes. Feeding management and sanitary conditions have a great influence on this disease. The disease is mostly transmitted through the respiratory tract. Newly affected herds have relatively high mortality among pregnant sows, while old affected herds have more piglet deaths. Mortality is even higher when there is secondary infection and mixed infection. This disease can slow the growth of affected pigs by about 12% and reduce feed utilization by 20%.

Symptoms and lesions: Newly affected herds show difficulty breathing, abdominal breathing, reluctance to move, and high mortality. Affected pigs do not have fever. The acute type is mostly seen in newly affected herds, manifesting as lethargy, reduced feed intake, respiratory rate reaching up to 120 breaths per minute, open-mouth gasping, foam from the mouth and nose, and a dog-sitting posture. Death can occur from suffocation, and surviving pigs turn into the chronic type. Chronically affected pigs show emaciation, rough hair, and stunted growth; arched back with dry coughing, neck extended, head lowered, until secretions in the respiratory tract are coughed up and swallowed. In the early morning when pigs are fed and during driving and exercise, continuous spasmodic coughing occurs, sometimes 10 to 20 times in a row, and the pig stands still while coughing. In the later stage, difficulty breathing and increased respiratory rate occur, with asthma developing, and affected pigs become emaciated and weak. The characteristic lesion is at the apices of both lungs. Vesicle skin and vesicle fluid are the most infectious, and recovered pigs can carry the virus for more than 150 days.

3. It can be transmitted through both direct contact and indirect contact. Infection and onset can occur through the digestive tract, respiratory tract, and undamaged mucous membranes and skin. Air is also an important transmission medium. The virus can spread with the wind to 50-100 kilometers away, causing long-distance and jumping outbreaks.

Symptoms and lesions: Affected pigs show lethargy, elevated body temperature reaching above 41°C, and reduced or absent appetite. The coronary band, interdigital space and toe area first become swollen and pale, then vesicles form. The vesicles contain transparent or turbid pale yellow fluid. After the vesicles rupture, red ulcerated surfaces remain. Vesicles and ulcers also commonly occur on the lips, tongue, gums, upper palate, nasal mirror and nipples, with profuse salivation. Affected pigs are lame, and some have deformed or sloughed hoof shells, making it difficult to stand. Postmortem examination of dead piglets shows pale yellow streaks on the surface of the heart muscle alternating with the red of the heart muscle in a tiger-stripe pattern, with hemorrhage in the endocardium and epicardium. The mortality rate of foot-and-mouth disease in adult pigs generally does not exceed 3%, and pregnant sows may abort. Piglets, especially suckling piglets, show no obvious vesicle symptoms after infection, but because myocarditis and gastroenteritis occur, they can die rapidly in a short time.

Diagnosis and prevention: The clinical features of swine foot-and-mouth disease are extremely similar to swine vesicular disease, swine vesicular stomatitis and swine vesicular exanthema, so diseased materials should be sent to the laboratory for confirmation. Diagnosis is easy based on symptoms and lesions (when conditions permit, neutralization tests, cross-immunity tests or complement fixation tests can be performed).

The prevention principle is "early, fast, strict, small." "Early" means early education, early screening and early detection. "Fast" means fast action, fast culling, fast disinfection and fast immunization. "Strict" means strictly implementing epidemic prevention measures. "Small" means making the epidemic area as small as possible to minimize losses. Strengthen feeding management and strictly implement veterinary sanitary and epidemic prevention measures in normal times. When the disease occurs, report immediately, confirm the diagnosis, delineate the epidemic area and epidemic point, carry out strict blockade and disinfection, and conduct harmless disposal of diseased and dead pigs. Immediately inject susceptible animals around the epidemic point and epidemic area with vaccine. Strict and thorough comprehensive disinfection can be carried out with 2% or 4% caustic soda water, 10% limewater, or Baidusha or sodium hypochlorite. After the epidemic is extinguished, livestock herds in the epidemic area and surrounding areas should continue to be vaccinated for 2-3 years.

Vaccines and immunization: Use swine foot-and-mouth disease vaccine matching the serotype for immunization. The injection immunization schedule is: sows at one and a half months before farrowing (mainly to protect newborn piglets), boars in September and December each year, piglets at 30-40 days after birth, and finishing pigs at 100 days of age with one more booster.