Effect of environmental enrichment at two stages of development on belly nosing in piglets weaned at fourteen days.

The incidence of belly nosing-related behaviors was studied in 480 piglets weaned at 14 d and provided with environmental enrichment during preweaning, postweaning, or both. Pen enrichment was achieved by providing a foam rubber mat on the pen wall (nose), rubber nipples (suck), a Bite-Rite Tail Chew (bite), a soil-filled tray (root), or no enrichment (control). Instantaneous scan sampling observations, at 5-min intervals, were conducted for 8 h (i.e., 96 scans/observation day) at 3, 10, 19, 26, and 33 d. Observations during the preweaning phase were made to determine the number of piglets lying, standing, nursing, and interacting with environmental enrichment. During the postweaning phase, observations were made to determine the number of piglets belly nosing, belly sucking, other nosing and sucking (other), biting, eating, drinking, and interacting with enrichment. The time-course for belly nosing was confirmed, with the behavior rising by 19 d, peaking by 26 d, and decreasing by 33 d (P < 0.001). Only nosing enrichment was found to reduce the incidence of belly-nosing behavior (3.8%) compared with controls (6.6%; P < 0.001). Pigs provided root enrichment spent more time manipulating their enrichment devices (30.2%) compared with all other enrichment groups (P < 0.001). Providing enrichment relevant to a particular behavioral vice as it commences, or shortly afterward, may have the greatest effect on reducing the incidence of that vice during the nursery period.