Do pigs find a familiar odourant attractive in novel surroundings?

Sixty-four Durocxlandrace pigs (Sus scrofa) of both sexes were reared from birth to 6 weeks of age in either fresh air or an atmosphere containing an artificial odourant (Ambi-Pur). Their behavioural responses to a novel envi ronment (a modified open held) were then observed over 1 h when the test ar ena contained either the familiar Ambi-Pur odourant or ammonia gas at 45 pp m. Although members of other mammalian and avian species are attracted to f amiliar odours in otherwise novel surroundings, the presence of Ambi-Pur ha d no effect on the pigs' readiness to enter the novel arena from a sheltere d area or on other fear-related behaviours following entry (p>0.05). Pigs k ept in fresh air from weaning until test were generally less active and spe nt less time at the centre of the open field if the test was carried out in an ammoniated atmosphere rather than fresh air; this suggests that they fo und ammonia aversive. On the other hand, the presence of ammonia at test ac celerated approach to the centre of the open field and increased the number of entries into that area and the percentage of time spent there as well a s overall activity in pigs that had also been exposed chronically to this g as at 43 ppm from weaning until testing at 6 weeks (p<0.05). Thus, after ch ronic exposure to either ammonia gas or an artificial odourant, ammonia was the only stimulus that appeared to act as an attractive agent for pigs pla ced in an otherwise novel environment. (C) 2000 Elsevier Science B.V, All r ights reserved.