Feeding behaviour of growing pigs using single or multi-space feeders

Abstract

Most studies of the feeding behaviour of group housed growing pigs have used computerized single-space feeders, which result in a pig:trough ratio which differs from that found on commercial pig farms, where multi-space feeding troughs are used. The present experiment compared the feeding patterns of group housed, growing pigs given access to either a computerized single-space feeder or a four-space feeding trough. Eighty cross-bred entire male pigs (initial live-weight 32.3 ± 0.62 kg; mean ± s.e.) were allocated to groups of ten, and each group given access to one of the two feeder types. The feeding behaviour was measured automatically fro the single-space feeders, and determined for the four-space trough treatment from video tapes, where feeder visits were counted and timed, combined with daily weights of the food eaten per group. Pigs given access to a four-space trough visited the feeder much more frequently (84.5 vs. 14.3 visits day −1; s.e.d. = 5.3; P < 0.001), and for shorter durations (0.67 vs. 4.67 min per visit; s.e.d. = 0.36; P < 0.001), eating only a little per visit (24 vs. 149 g per visit; s.e.d. = 14; P < 0.001) compared with pigs kept in the groups given access to a computerized single-space feeder. High levels of allelomimetic feeding were shown by pigs using the four-space trough, with 61% of all visits initiated whilst one or more pigs were already feeding. Also, a higher proportion of visits were made adjacent to a feeding pig than would have been expected by change (0.59 vs. 0.50; P < 0.001). No significant differences were found between treatment in the rate of feeding or daily feeder occupation. The differences in feeding pattern did not result in differences in production variables in terms of daily feed intake, daily live-weight gain, and feed conversion ratio. A bout analysis was applied to the data using frequency distributions of length of intervals between visits. For pigs using the four-space trough visits could justifiably be collapsed into feeding bouts, whereas this was not the case for visits displayed by pigs using the single-space feeder. Pigs using the four-space trough showed a high frequency (0.64) of changes between spaces within each feeding bout. This may represent exploratory or sampling behaviour, which may aid the pig in obtaining a nutrient-sufficient diet should many different food items be available. Comparing feeding bouts from the four-space feeders to visits from the single-space feeders revealed no differences between the two types of feeders, indicating that single-space feeders constrain the feeding pattern mainly in terms of preventing changes between trough-spaces within bursts of feeding.