Nutritional management of group-housed gestating sows - key challenges in the transition from stall-housing systems

Transition from gestation stalls to group-housing systems is a source of trepidation for many pork producers, given the capital cost of conversion and the challenges associated with managing sows in groups. Despite this, market imperatives in Australia have led to rapid transition in many enterprises. The cost of conversion of a 4100-sow unit from stalls to groups using low-cost retrofitting of existing breeder space (AU$150.00/sow) at relatively high densities (1.8 m(2)/sow) in small static groups (15-20 sows) based on floor or trough feeding with or without head bales and shoulder partitions equates to an additional cost of $3.00/piglet weaned if the level of productivity is maintained. If the number of piglets born per litter is increased by 1.04 piglets per litter, overall earnings of the herd are equal to levels achieved before the transition. This capital cost appears manageable if appropriate nutritional regimens are implemented to address individual nutritional needs of sows housed in groups and to manage aggression. Management of sow body condition during the reproductive cycle focussed on standardised gilt introduction to the breeding herd and optimisation of sow and gilt feed intake in lactation is pivotal, as it reduces the need for remedial feeding of individual sows post-weaning and during gestation. Nutritional management can also be used to reduce aggression between sows by removing impediments to feed access and by induction of satiety. Commercial implementation of these strategies confirms their relevance and demonstrates that sows can be cost-effectively managed in group-housing systems.