Intermittent suckling with or without co-mingling of non-littermate piglets before weaning improves piglet performance in the immediate post-weaning period when compared with conventional weaning.

Background: In this experiment, intermittent suckling (IS) with or without the co-mingling (CoM) of piglets was studied as a method to stimulate solid feed intake and reduce post-weaning stress.
Methods: Three weaning regimes using 30 multiparous sows were compared: (1) conventional weaning (CW) ( n  = 10 litters), where piglets had continuous access to the sow until weaning (d 0, farrowing = d -25 relative to weaning); (2) intermittent suckling (IS) ( n  = 10 litters), where piglets were separated from the sow for 8 h/d starting at d -7 (relative to weaning); and (3) intermittent suckling with co-mingling (ISCo) ( n  = 10 litters) where IS started at d -7 and two litters were housed together during separation and then returned to their original sow. Ad libitum creep feed was available from d -17. At weaning pigs were housed in pens of 11 pigs, 27 pens in total. The ISCo treatment was divided in half to examine effects of different mixing strategies after weaning. Half of the ISCo litters were kept in familiar groups (ISCoF, familiar, n  = 4) and the other half were mixed within treatment resulting in groups of unfamiliar pigs (ISCoNF, not familiar,  n  = 5), the same as IS ( n  = 9) and CW ( n  = 9) treatments.
Results: The ISCo piglets ate more creep feed in the week before weaning ( P  < 0.01), but also showed more aggressive and manipulative behaviour on first day of CoM compared with CW piglets ( P  < 0.05). IS with or without CoM increased exploratory and play behaviour on the first day of treatment intervention ( P  < 0.001) and increased sleeping behaviour on the last day of treatment intervention compared with CW ( P  < 0.001). Mixing strategy at weaning had an effect on performance data with the highest growth and feed intake seen in ISCoF pigs 2 to 8 d after weaning ( P <0.001). IS and ISCoNF pigs also grew faster and ate more than CW pigs 2 to 8 d after weaning (P < 0.001). Post-weaning injury scores suggested reduced aggression in ISCo as evidenced by reduced redness (skin irritation) ( P  < 0.05), and a tendency for ISCo to have less scratches than CW ( P  < 0.1). The IS pigs slept the most and displayed less manipulative behaviours on the day of weaning and plasma haptoglobin levels remained low in IS pigs after weaning ( P  ≤ 0.01).
Conclusions: Both intermittent suckling techniques improved production indices in the immediate post-weaning period. However, the addition of co-mingling before weaning in combination with grouping familiar pigs together after weaning improved performance in an additive manner.