Farm Animals

Farmed Pig Worm Burden and Welfare

Internal parasites in pigs cause welfare harm and production losses, particularly in outdoor and organic systems with soil exposure.

Key Facts

Ascaris suum (large roundworm) is the primary parasite of pigs with outdoor access
Liver milk spot lesions from migrating larvae cause permanent welfare markers
Outdoor pigs have significantly higher worm burdens than indoor pigs
Anthelmintic treatment is effective but must be timed appropriately
Pasture rotation breaks parasite lifecycles in outdoor systems

Welfare Considerations

Pigs with high worm burdens suffer from nutrient competition, liver damage, and reduced immunity. Liver lesions found at slaughter provide retrospective welfare evidence of parasite burden. Strategic anthelmintic treatment and pasture rotation in outdoor systems are essential welfare management tools.

What You Can Do

Support parasite monitoring standards for outdoor pig systems
Advocate for veterinary parasite management guidance in outdoor pig welfare codes
Choose outdoor pork from farms with documented parasite management protocols