The prevalence of some economically important swine diseases in farrowing units in southwestern Finland

The prevalence and geographical distribution of some economically important swine diseases were surveyed in 114 randomly selected farrowing units which had a contract with Southwestern Finland's Cooperative Slaughterhouse (LSO) for producing feeder pigs to be delivered to the all in-all out finishing units. The focus was on infectious diseases which could be transmitted to the finishing units with delivered growers, and which might have some influence on partial carcass condemnations (PCC) in meat inspection. Farm visits were done by a veterinarian (senior author) assisted by a technician. Colostrum samples (average 22 per herd) were taken in 100 herds, and analyzed for Actinobacillus pleuropneumoniae (A. pleur) and Mycoplasma hyopneumoniae (M.hyo) antibodies by enzyme-linked immunosorbent assays (ELISAs). Only nine of 114 herds were judged to be free of mange. It was concluded that all finishing units received mange-infected feeder pigs each time the unit was filled. One or more acute erysipelas outbreaks had occurred in every fifth herd during the previous year. The risk of a finishing unit receiving feeder pigs carrying erysipelas was considered to be high. Swine dysentery (Serpulina hyodysenteriae) was not found to be a problem in the LSO area. Clostridium perfringens type C enteritis was found in eight (7%) herds. Seven of these herds were located in those supply areas where the PCC percentage of feeder pigs was high. In spite of statistical connection no causality between this disease and PCC was presumed. There were no previous diagnoses of respiratory diseases but spontaneous coughing was observed in 5% of the herds. Provocation testing induced coughing in 22% of herds but not serious coughing in any herd. Managers had observed coughing in 15% of herds. Ninety-one herds were positive in a colostrum ELISA for A. pleur antibodies, and eight herds were positive for M.hyo antibodies. A.pleur-positive herds had several positive or samples suspected of being positive in each herd bu M.hyo-positive herds had only one or two positive or suspected samples per herd. Six of the M.hyo herds were located in the high PCC area, two in the average PCC area and none in the low PCC area. M.hyo was suggested to be one of the possible explanations for geographical variation of PCC. Atrophic rhinitis was not considered to be of importance in LSO.