Development of ingestive behaviour and the relationship to belly nosing in early-weaned piglets

Over the last 30 years, improvements in diet formulations have resulted in a steady decline in weaning age while still meeting the nutritional needs of the piglets. However, even with their dietary requirements met, many piglets still experience a number of difficulties at weaning. Piglets weaned prior to 4 weeks-of-age typically take longer to ingest solid feed, drink excessively and develop oral behaviour problems such as belly nosing and belly sucking. There is considerable variation in the amount of time individual piglets spend belly nosing, and factors such as weaning weight and suckling behaviour on the sow do not reliably predict which piglets will belly nose. However, those piglets that spend more time belly nosing also spend less time at the feeder and have poorer growth rates, and there is growing evidence that feeding, drinking and sucking motivation are linked in the early-weaned piglet. In this article, we review current knowledge on the development of feeding, drinking and belly nosing in order to illustrate the relationships among the sucking, feeding and drinking motivational systems in the early-weaned piglet. We also explore differences in the tendencies of individual piglets to develop problems at weaning and how genetic and environmental factors may play a role in these differences.