Detection And Control Of Respiratory Syndrome In One Point Pig Farm

Porcine Respiratory Disease Syndrome(PRDC)is a multifactorial disease that is caused by a combination of viruses,bacteria,poor feeding and management environment,and susceptible pigs.PRDC is involved in a variety of pathogens causing respiratory diseases,including primary infection and secondary infection.The primary diseases include Mycoplasma pneumoniae,atrophic rhinitis,reproductive and respiratory syndrome,porcine circovirus type II,Swine flu,porcine pseudorabies,swine plague,porcine erythroblastosis,toxoplasmosis,aphid larvae infection.On the other hand,the secondary diseases are associated with haemophilus parasuis,infectious pleuropneumonia,etc.In addition,environmental management factors such as herd density,diurnal temperature difference,ambient air quality,wind speed are closely related to PRDC.The hazards of this disease are economic losses such as increased death rate,lower feed conversion rate,slower growth,delayed listing,lower quality of pigs,and serious deaths from serious cases.With the improvement of the level of pig industry in China,all large-scale pig farms pay attention to the prevention and control of PRDC and take corresponding control measures,but the losses caused by PRDC are still immeasurable.The farm involved in this research is a large-scale pig farm with 3,600 sows and 80,000 fattening pigs.At the end of 2016,all the fattening pigs showed different degrees of PRDC symptoms,and more than 10% of pigs got cough.Acute deaths occurred in some 20-week-old pigs in the late fattening period.The main symptoms were mouth and nose bleeding of dead pigs.The necropsy findings of dead pigs showed that hemorrhagic lobar pneumonia,lung diaphragmatic leaves with obvious lesions,redness and swelling slightly hard,red liquid in the chest.The lungs of acutely dead pigs are dark purple,solid and covered with fibrous exudates.Chronic death sick pigs showed significant fibrotic pleuropneumonia lesions,adhesion of the lungs to the chest wall,pericardial effusion or fibrinous adhesions.It was initially suspected infectious pleuropneumonia(APP).The lungs,spleen,tonsils,lymph nodes and other organs were taken to the laboratory for PRDC-related pathogen detection.They were diagnosed with herd acute infection of infectious pleuropneumonia(APP)by on-site necropsy and laboratory diagnosis.Besides,porcine reproductive and respiratorysyndrome virus(PRRSV),pseudorabies virus(PRV),swine flu vius(SIV),porcine circovirus(PCV),mycoplasmal pneumonia(MPS),and atrophic rhinitis(AR)were follow-up detected.It was found that the direct cause of the occurrence of PRDC in the fattening pigs was the prevalence of APP,and the pathogenesis was strong stress factors caused by environmental changes.In addition,the prevalence of PRRSV,PRV,and MPS greatly contributed to the onset of APP,which made the PRDC problem prominent.Drug prevention and control can effectively reduce the incidence of PRDC,but in the case of improper management of environmental factors,the drug prevention and control effect will be greatly affected,combined with the consideration of food safety factors,is not the fundamental way to solve the PRDC problem.Ventilation,density and feeding models have a significant impact on the PRDC issue.The environmental control of swine pens and equipment operation specifications and production mode adjustment are important measures for the prevention and control of PRDC in modern scale pig farms.