Detailed Explanation of Prevention and Treatment Methods for Porcine Respiratory Disease Complex

Regarding the situation in a pig farm in western Shandong where respiratory disease was more severe in growing-finishing pigs than in nursery pigs, quite a lot of medication was used for control without achieving good results, which is what farmers call: "spent good money but didn't get good results."

Since 2005, piglets in many pig farms have developed pneumonia, coughing and cyanosis of the ears in some pigs. Growing pigs over 25 kg mainly showed coughing and panting as well as dermatitis. Compared with 2005, when the disease onset was mainly characterized by diarrhea symptoms, it has now shifted to being mainly characterized by respiratory symptoms along with coughing and spraying of feces. In the hot climate of summer and autumn, many round red patches protruding from the skin surface are seen on the pigs' bodies. The immunization programs on the pig farms are all relatively simple: the sow herd is immunized with RespiSure mycoplasma vaccine and vaccines for swine fever and pseudorabies, etc.; many are not immunized with PRRS or PCV vaccines. Piglets are immunized with vaccines for swine fever, streptococcus, etc.

Observing from the farrowing house, nursery barn and finishing barn, respiratory symptoms are most obvious in the growing pig barn, with pigs showing coughing symptoms in almost every pen, presenting as dry cough without phlegm and spraying of feces from the anus. Severely affected pigs show abdominal breathing, lie down, are unwilling to move, have tear stains around the eyes, and some have purple ears, with a body temperature of 39°C~40.5°C, eating little or not eating, and passing loose feces. Necropsy of pigs with purple ears revealed bleeding throughout the lungs, with fibrinous exudate causing the lungs to adhere to the chest cavity, and fibrinous exudate on the serosal surface causing intestinal adhesions, with enlarged lymph nodes but no obvious hemorrhage. Based on clinical symptoms and necropsy observations, a preliminary diagnosis can be made as porcine respiratory disease complex (PRDC).

Last year, many pig farms showed the above symptoms, mainly involving enzootic pneumonia and infectious pleuropneumonia, and at the same time related to latent infection with blue ear disease (PRRS); immunosuppression caused by mycotoxins was also one of the predisposing factors.

Preventive Measures

Strengthen feeding management. Pay attention to isolated rearing; newly introduced breeding pigs should be raised in isolation for more than 40 days.

Sick pigs should be raised in isolation, and those that should be culled should be culled promptly.

Adhere to all-in/all-out; the farrowing house and nursery barn should adopt the all-in/all-out production method.

Do a good job of hygiene and disinfection. When the barn is empty, thoroughly clean and disinfect it, leave it vacant for 7 days, and then move in a new group of pigs.

It is strictly forbidden to foster sick and weak piglets from the previous batch into the next batch.

Pay attention to stocking density; the occurrence of respiratory disease is closely related to stocking density. If conditions are poor, the density should be lower.

Pay attention to ventilation and temperature control.

Reduce stress and minimize the number of times pigs are moved between pens and mixed into groups; when piglets are weaned, do not change pens or change feed; after weaning, piglets continue to be raised in the farrowing house for 7 days before being transferred to the nursery barn; try not to vaccinate on the day of weaning; feed changes at each stage should be gradually transitioned.

Immunization

Based on the actual epidemic situation in the local area and on the farm, scientifically formulate an immunization program suitable for the farm and strictly follow and implement it.

Strategic phased medication for prevention.

Sows

Medications used: Zhujiansu or Zhuchuankang. Usage: mixed into feed within 2 weeks after mating and within 2 weeks before and after farrowing, used continuously for 1 week to 2 weeks.

Boars and Replacement Pigs

Medications used: Zhuchuankang or Zhiyuanqing. Usage: use once every 3 weeks to 4 weeks, mixed into feed, used continuously for 1 week.

Piglets

Medications used: Chuankeliting, Yayixiao, Baoyukang.

Usage: nasal spray of Chuankeliting or Yayixiao once each at 1 day of age and 7 days of age after birth; Baoyukang mixed into feed before and after weaning, used continuously for 7 days.

Nursery Pigs and Growing Pigs

Medications used: Zhuchuankang or Zhiyuanqing. Usage: after moving groups and changing feed in the two stages, mix Zhuchuankang or Zhiyuanqing into feed for 1 week respectively.

Finishing Pigs

Medication used: Meifei. Usage: mixed into feed for 40 days before slaughter.

Treatment Measures

During treatment, therapeutic drugs should be kept separate from preventive drugs.

Recommended therapeutic drugs include: Lanhuan Shuangbo, Fulaixin, Huaxi Chaoli, Yayixiao and other injectables; see the instructions for usage.

Because some pig farms have concurrent viral diseases such as blue ear disease (PRRS), it is recommended to use one of the above drugs in combination with Xinbituo.

On farms with severe mycotoxin problems, the entire herd should be given Meiduqing mixed into feed for one week every other month.

In addition, individual treatment should be combined with whole-herd medication; when respiratory disease occurs, individual treatment by intramuscular injection or nasal spray should be carried out for severely affected pigs, while the whole herd should be medicated through feed or drinking water; after symptoms disappear, treatment should continue for 1 more course to prevent relapse; if the incidence of respiratory disease is very high and relatively severe, pulse-style preventive or therapeutic medication should be given to each pig group at certain time intervals, such as 1 week of medication followed by 2 weeks to 3 weeks off medication, which can reduce the incidence and allow effective control of the disease.