A study of the influence of various animal husbandry criteria on the occurrence of PMWS (Postweaning Multisystemic Wasting Syndrome) in an experimental pig farm

Data on PMWS (Post-weaning Multisystemic Wasting Syndrome) were collected over a one-year period on the experimental pig farm located at Romillé. The prevalence of the disease was estimated by autopsying all dead pigs, by recording clinical symptoms and by regularly weighing the pigs (every 15 d) during the first two months of fattening.The repercussions of the disease were high; both on the percentage of animals which were ill or died (mortality rate during fattening reached 8%) and on growth rate (-264 g/d over the first four weeks of fattening). The occurrence of PMWS was unaffected by litter size, by parity and by reducing the number of piglets adopted in the farrowing house. In addition, when two groups of piglets were studied, the appearance of the disease was not affected by keeping piglets from the same litter together after weaning. However, castrated male pigs were more susceptible to PMWS than females (38% vs. 29%, respectively). Pigs were more frequently affected by the disease when they had lower birth and weaning weights and when they were lighter at the beginning of the fattening period.