The effects of changing straw provision on the feeding behaviour and activity of growing pigs given food through single-space feeders

In a previous experiment the provision of straw to group-housed pigs increa sed the number of daily feeder visits. This effect of straw is comparable w ith conditions of reduced social competition for access to the feeder. The aim of this experiment was to investigate if changing straw provision withi n a pen resulted in similar and reversible effects in this behaviour. One h undred and twenty male pigs (41.1 (s.e. 0.43) kg) were used in three blocks each of four pens of 10 pigs. In each block of 42 days duration one pen ha d no straw throughout (treatment 1); one pen had no straw for 21 days (peri od 1) followed by straw for 21 days (period 2) (2); one pen had straw follo wed by no straw (3) and one pen had straw throughout (4). The pens were sit uated in a naturally ventilated building with light from 06.00 to 20.00 h. Each pen had a kennel, a lying area and a single-space computerized feeder for recording feeding behaviour. The pigs' activity was recorded on video i n the 2nd and 5th weeks of each block. The number of feeder visits was slig htly higher for pigs with straw (1: 9.69 v. 4: 10.46) but this was not sign ificant (P > 0.05). The effect was more marked for treatment 2 where the vi sits increased (P < 0.01) from period 1 (8.52) to period 2 (10.64) and for treatment 3 where they decreased (11.20 v. 10.10). Pigs without straw (trea tment 2) spent more time in the kennel than those with straw (treatment 4) (P < 0.05). For treatment 2 the proportion of time spent in the kennel fell from 0.607 in period 1 to 0.288 in period 2 (P < 0.01). There was a genera l trend for more activity and more lying outside the kennel when straw was provided. The effect of straw provision was not as marked as that seen prev iously; nevertheless changing straw provision (treatments 2 and 3) did resu lt in all increase in feeder visits with straw, probably related to the inc rease in general activity and lying outside in the area adjacent to the fee der.