FOOD SUBSTRATES AS ENVIRONMENTAL ENRICHMENT FOR PIGS

The behaviour of 24 Large White x Landrace gilts (83 kg) housed in gro ups of six in straw pens were observed by scan-sampling from 0900-1200 hrs over four weeks. They received 1.5 kg daily of complete barley-ba sed diet and were subjected to each of our treatments in a 4 x 4 Latin -square design: no addition ('Control'); 6 kg of additional straw ('St raw'); 1.5 kg feed scattered amongst bedding ('Feed'); 10 kg turnips/p otatoes ('Roots'). Inactivity was highest in Control (36.1%) and lowes t in Roots (6.7%) (p<0.05). Pen-directed behaviour was also highest in Control (6.9%) and lowest in Roots (1.5%) (p<0.05). Less time was spe nt feeding at the trough in Roots (p<0.05). Agonistic behaviour did no t differ significantly between treatments (mean: 1.1%). The order of i ncreasing foraging behaviour was Control (19.3%); Straw (31.9%); Feed (37.3%); Roots (62.8%) which was consistent over days. in the first th ree treatments, foraging was mainly exploratory and straw-directed and decreased between 0900 and 2200 hrs. In the Roots treatment, foraging was significantly greater (p<0.05), mainly root-directed and did not decrease between 0900-1200 hrs. Root-directed behaviour changed from e xploratory behaviour to ingestion over the experimental period. The be haviour of the gilts indicated that the order of increasing environmen tal enrichment provided by the four treatments was: Control; Straw; Fe ed and Roots respectively. However, in commercial practice, the daily addition of fresh straw would probably be a more suitable substrate fo r promoting natural foraging behaviour as it is relatively inexpensive and readily available.