Immediate behavioural consequences of fostering 1-week-old piglets

Abstract

SUMMARYTwenty-four sows and their 4- to 7-day-old litters were observed in batches of four for approximately 2h to ascertain piglet teat preferences and timings of suckling periods. In each batch, two litters were then selected to have two piglets exchanged between them while the other two remained intact as controls. In the subsequent 3 h, sows with fostered piglets initiated significantly more suckling periods than controls; but many were disturbed at an early stage and only 35% of such periods resulted in milk letdown (compared with 93% in controls). Many sows displayed aggression specifically towards fostered piglets. Many fostered piglets showed signs of distress and attempted to escape. Fostered piglets were significantly more likely to take 10 sec or more from the start of suckling to approach the udder, and less likely to be sucking at milk letdown. Many of these effects were greater when piglets had to compete with a resident piglet with the same teat preference and all were still evident in the third of the three observation hours.