The Diagnosis Of Mycoplasmal Pneumonia And The Establishment Of Negative Pigs

Mycoplasmal pneumonia of swine(MPS)is also known as swine enzootic pneumonia and pig asthma.MPS,caused by Mycoplasma hyopneumoniae(Mhp),is a chronic respiratory disease of finishing pigs that manifests as coughing,retarded growth and poor feed conversion efficiency.The disease causes significant economic losses due to increased medication use and decreased performance of the pigs.Prevention of the development of MPS is a continuing problem to the swine industry worldwide.Effective control of MPS is based on control and purification mycoplasmal pneumonia of swine at the sources.Based on our previous results about Mhp control and its pathogenic mechanisms,the control methods of diagnosis of Mycoplasmal pneumonia and a new breeding technology combining with drug therapy,Segregated Early Weanling(SEW)technique and three-site production technique was performed in this study.As a result,190 mycoplasmal pneumonia-negative breeding pigs were established.The main body includes:(1)The diagnosis of Mycoplasmal pneumonia:A certain mycoplasmal pneumonia-positive farm with infection symptoms was selected.According to feeding and management procedures,vaccination except that against Mhp was carried out.Observation of clinical symptoms,coughing index,statistical analysis,serum antibody detection,anatomy score,pathogen analysis and nested PCR assay were carried out to identify mycoplasmal pneumonia.As a result,a farm was identified as a pneumonia-positive farm,which was used as a management system for control and purification of mycoplasmal pneumonia.(2)The establishment of negative pigs:To explore a breeding method for Mhp-negative swine population,the purifying effects of combination therapy,SEW and three-point breeding and management system on Mhp were investigated in this study.After the processes of screening pregnant sows,programmed therapy for sows,SEW,three-point breeding and management in the barrier isolation system and programmed therapy for piglets,the newly-bred(190 in five batches)piglets were monitored as long as four months by serum antibody detection of Mhp and fluorescent quantitative PCR of nose swabs.The results showed that when the newly-bred five batches of piglets were older than 35 d,they were all negative by serum antibody detection and nose swab antigen detection.Therefore,the combination therapy,SEW and three-point production and management system can effectively purify Mhp.The results showed that providing mycoplasmal pneumonia-negative breeding pigs for healthy nuclear breeding population was benefit for control and purify mycoplasmal pneumonia of swine at the sources,thereby providing theoretical basis and practical experience for domestic control and purification of mycoplasmal pneumonia.