Effect of housing system on sow productivity.

Three separate trials are described, each involving sows ranging in parity from first to tenth. In the first trial sows were penned either in individual stalls 2.1 m X 0.6 m or individually tethered in stalls 0.6 m wide, from mating to day 110 of pregnancy. Both groups were on insulated concrete floors partially slatted. Results indicate no difference in percentage of pigs born dead or survival to weaning or in post-weaning performance of sows. In the second trial sows were kept in farrowing pens 2.4 m X 1.6 m with the sow restrained in a farrowing crate 0.6 m wide or tethered by the neck in a partial crate 0.6 m wide from day 110 of pregnancy to weaning at 30 days of age. All pens were of insulated concrete without bedding with the rear 0.6 m slatted with cast iron slats. Results indicate no effect of pen type on percentage of pigs born dead, survival to weaning or in post-weaning sow performance. In the third trial sows were housed in groups of 4 on an insulated concrete floor without bedding or in individual stalls after weaning. Boars were present in adjoining pens in both cases. Group housed animals had poorer performance due to a combination of failure to show oestrus, lower conception ratio and loss through injuries due to fighting. Those that did show oestrus had the same weaning to oestrus period as stalled sows and produced slightly (but not significantly) bigger litters.