Farm Animals

Pig Wean-to-Service Interval Welfare

The wean-to-service interval (WSI) in sows links reproductive welfare to management, with short WSIs linked to poor subsequent fertility and sow welfare.

Key Facts

WSI is the number of days between weaning piglets and subsequent mating
Standard WSI is 3-7 days; very short intervals are associated with reduced ovulation rate
Lactation feeding management strongly influences WSI through body condition and metabolic status
Thin sows at weaning have extended WSI and reduced subsequent litter size
Optimising WSI through nutrition and management improves both sow welfare and farm output

Welfare Considerations

The wean-to-service interval reflects underlying sow welfare through the effects of lactation stress and nutritional management. Optimising it requires attention to the whole reproductive cycle.

What You Can Do

Support farms that monitor sow body condition and WSI as welfare indicators
Advocate for sow nutrition standards that prevent excessive lactation weight loss
Ask producers about their sow body condition management and WSI monitoring protocols