PMWS in Pigs: Welfare During Wasting Disease Outbreaks
Post-weaning multisystemic wasting syndrome (PMWS) caused by porcine circovirus 2 causes severe wasting in young pigs, creating significant welfare emergencies on affected farms.
Key Facts
- PCV2 infection interacting with other stressors causes immune dysfunction and wasting
- Affects pigs primarily 5-12 weeks after weaning with rapid deterioration
- Signs include progressive weight loss, pallor, jaundice, respiratory signs, and death
- Vaccination against PCV2 is highly effective at preventing clinical PMWS
- Weaning management and stocking density strongly influence disease expression
Welfare Considerations
PMWS creates acute welfare suffering through rapid wasting, immune collapse, and multi-organ failure in affected piglets. Pigs with PMWS deteriorate quickly, becoming thin, weak, and unable to compete for food and water. Secondary infections exploit the immune suppression, causing additional suffering. The high mortality in PMWS outbreaks represents both individual welfare failure and a systemic farm welfare problem. PCV2 vaccination has dramatically reduced PMWS prevalence, demonstrating that this serious welfare problem is largely preventable. Prompt identification and euthanasia of severely affected pigs prevents prolonged suffering.
What You Can Do
- Implement comprehensive PCV2 vaccination programs for all piglets
- Optimize weaning management to minimize stress that triggers disease expression
- Monitor post-weaning pigs closely for early signs of wasting and pallor
- Euthanize severely affected pigs promptly to prevent prolonged suffering
- Review stocking density and mixing protocols to reduce disease risk