Daily food intakes and feeding strategies of sows given food ad libitum and allocated to two different space allowances in a communal farrowing system over parturition and during lactation.

A total of 16 multiparous (range 2nd to 9th parity) Camborough sows were housed over parturition and during lactation in a group farrowing system. Two replicates of four sows were studied in the large pen (L) and two further replicates studied in the small pen (S) configuration, providing 13•4 m 2 and 8•6 m 2 per sow, respectively. A lactation diet providing 14 MJ/kg digestible energy (DE) and 180 g/kg crude protein was supplied ad libitum via a sow-operated feeder, adapted to facilitate the calculation of individual food intakes. The influence of environmental, physical, and production factors upon food intakes and feeding strategies was investigated. Daily food intakes of 7•69 (s.e. 0•31) kg and 7•72 (s.e. 0•35) kg were achieved during lactation by sows in the L and S pen configurations, respectively, accomplished by sows taking a series of small meals throughout the day. Sows in the S pen area made fewer visits to the feeder and spent less time per day feeding than sows in the L pen area. However, more food was consumed per visit by the S sows, resulting in similar daily food intakes in both treatment groups. There was a depression in lactation food intakes of sows housed at a mean daily ambient temperature of 17•5oC compared with the other sow groups. The majority of sows consumed energy well in excess of their predicted requirements during lactation, whilst one sow in the L and two in the S pen areas had intakes within ±3•4 MJ DE of predictions. Only two of the L sows had food intakes that produced an energy deficit. In the L pen area, two distinct peaks of feeding activity occurred from 09:00 to 13:00 h and from 15:00 to 23:00 h that accounted for 0•77 of the total feeding time. In contrast, in the S pen configuration, one prolonged period of feeding occurred from 09:00 to 22:00 h accounting for 0•88 of total feeding time. The results show that S sows adapted their feeding patterns to maintain similar daily intakes to those of L sows, thus demonstrating that an ad libitum food supply enabled sows to obtain individual nutritional requirements in a communal farrowing system.