In swine, swine dysentery due to B. hyodysenteriae typically affects which age group?

• A. Neonatal piglets
• B. Weaned pigs 6-12 weeks
• C. Adult sows
• D. All ages

Answer: (B)

The main idea here is that swine dysentery from B. hyodysenteriae commonly hits pigs just after weaning. The shift from milk to solid feed and the stress of weaning disrupt the gut environment and local immunity, allowing the organism to colonize the large intestine and cause necrotizing colitis with mucohemorrhagic diarrhea. Neonatal piglets usually fare better because maternal antibodies and the developing gut microbiota offer protection, while adult sows often have prior exposure and immunity that reduces or prevents clinical disease. So the age group most typically affected is weaned pigs around 6–12 weeks, when susceptibility is highest due to the combined effects of weaning stress and immature, transitioning gut defenses.