Foraging in the farrowing room to stimulate feeding : getting piglets to eat is bittersweet

In common pig production systems, weaning happens early and abruptly, which contrasts the gradual transition from sow’s milk to solid feed in nature. A significant proportion of commercially reared piglets is therefore poorly familiarised with the ingestion of solid feed before weaning, which together with concurrent changes in social structure and environment, result in a low feed intake and multiple health and welfare problems initially after weaning. The first aim of this thesis was to investigate the effects of solid feed provision during lactation (creep feed) on piglet development during the weaning transition. Piglets provided with creep feed (including fermentable fibres) during lactation increased their growth towards weaning, tended to be heavier at weaning, and were heavier and more uniform in body weight at two weeks after weaning compared to piglets reared on sow’s milk only. This may partly be explained by a more developed gastrointestinal tract and more mature gut microbiota population at weaning of creep feed eaters within litters given creep feed. The second aim of this thesis was to explore whether piglets that were offered more opportunities to forage early in life increased their intake of creep feed before weaning and thereby improved their ability to deal with the weaning transition. Four strategies that could stimulate foraging in the farrowing room were tested: 1) enriching the pen with foraging materials on the floor and extra space, and by alternating chew objects, 2) presenting creep feed in a ‘play-feeder’ with foraging and playing materials attached, 3) providing diverse feeds in the feeder and 4) hiding feed in the feeder in sand. Enrichment with foraging materials on the floor, more space and alternating chew objects positively influenced feed intake of piglets before and after weaning until the end of the study at 2.5 weeks post-weaning. Presenting the creep feed in a play-feeder stimulated feeder exploration and attracted more piglets than presenting the feed in a conventional feeder. Although the play-feeder did not enhance pre-weaning feed intake, post-weaning feed intake and growth were substantially improved and the incidence of diarrhoea, body lesions and damage were lower. Simultaneous provision of diverse feeds to suckling piglets resulted in more feed exploration and solid feed intake, and in a higher number of good eaters. Hiding feed in sand stimulated the number of good creep feed eaters within the litter, but did not increase exploration towards the feed. With the exception of the first feeding strategy, treatments were not reinforced after weaning and piglets thus experienced loss of these resources, which may have had a negative effect on post-weaning adaptation. This may explain the limited effects of dietary diversity on post-weaning adaption and the negative effects of hiding feed in sand on post-weaning feed intake, growth, manipulation and aggression. Lastly, it was shown that creep feed intake is not only driven by exploration, but also by a low energy intake from milk. Increased creep feed intake by litters with a low milk intake may counteract the growth lag they developed during lactation by improving pre-weaning feed intake and, consequently, initial post-weaning feed intake and growth compared to litters that consume more sow’s milk. In conclusion, creep feed provision and consumption accelerated piglet development, and improved opportunities for early foraging consistently enhanced the development of feeding behaviour. If one wants to improve post-weaning adaptation of piglets, a ‘mismatch’ in environment should be avoided.