The interval between weaning and return to oestrus in sows is a welfare-relevant reproductive period influenced by nutrition, body condition, and management.
Extended WSI reflects sow metabolic stress from inadequate nutrition during lactation or excessive body condition loss. Management that prevents condition loss during lactation through targeted feeding reduces the duration of the post-weaning anoestrus period. The sow's reproductive welfare is directly linked to her nutritional welfare during the preceding lactation.