Eradication of Mycoplasma hyopneumoniae from infected swine herds joining the LSO 2000 health class

The study was conducted in order to determine if eradication of swine enzoo tic pneumoniae (SEP) had succeeded with different variants of partial depop ulation during the eradication programme on swine farrowing farms joining a health class, LSO 2000. The farms in the health class need to be free from swine enzootic pneumoniae, swine dysentery, sarcoptic mange and atrophic r hinitis. Twenty-one eradication attempts for M. hyopneumoniae were carried out using different variants based on separating adult animals for 2 weeks from infected young pigs which were not returned to the herd. The infected young pigs were kept in the same building (variant 1) in 4 herds and on the same compound (variant 2) as disease-free pigs in 12 herds. The infected y oung pigs were finally all sold. In 5 herds only adult animals were present during the eradication (variant 3). The eradication attempt succeeded in 8 1% and failed or remained uncertain in 19% of the herds. The result was con firmed with 1) frequent clinical follow-up of the health status in the herd s (both the farrowing and the finishing units) joining the LSO 2000 health class 2) milk and/or brood serology. Possible causes of the failure of the eradication attempt were described: a short distance between infected and u ninfected animals, the time period between diagnosis of SEP and initiation of the programme, the age of the youngest animal kept on the farm, the peri od of time when animals with different status were reared close to each oth er, the medications used, the cleaning of the facilities during the program me and the season. Further, a good cooperation between the farmer, the loca l veterinarian and the animal health service of the slaughterhouse was an e ssential part of the initiation and the follow-up of the programme. The sec ondary aim of the study was to collect information about the expenses durin g the programme. Only 57% of the farmers gave some estimates for the expens es on their farms. For variants 1, 2 and 3 the expenses were 879, 1110 and 1274 FIM per sow (1 USD = 5.5 FIM), respectively (p>0.1).