Feed intake behaviour of group-housed Pietrain and Large White growing pigs

Feed intake behaviour traits were recorded on 210 Large White and 114 Pietr ain entire male pigs housed in single-breed groups (range of group size: 8- 13) and having 24 h access to 'Acema 48' electronic feed dispensers. Three stages of growth were considered (average body weights of 39, 64 and 89 kg for both breeds), and feeding behaviour traits were calculated separately f or two periods of the day (8-20 h and 20-8 h). Slower-growing and leaner Pi etrains compared with Large Whites displayed a much lower dairy feed intake lever (1.72 vs. 2.12 kg, P < 0.001) as well as a different feed intake pat tern, consisting of much less feeder visits per day (8.8 vs. 15.7, P < 0.00 1), shorter daily eating time (49.7 vs. 55.6 min, P < 0.001), smaller daily number (5.84 vs. 6.53, P < 0.05) and average size (300 vs. 332 g, P < 0.05 ) of meals, and slower rate of feed intake (34.8 vs. 38.1 g.min(-1), P < 0. 01). Average time per meal (9.4 min), however, was not breed-dependent. Bot h breeds followed similar trends in feeding behaviour over the course of gr owth, even though the breed by stage of growth interaction was revealed to be significant for several traits. The nychthemeral distribution of feed in take was around 70% and 30% feed consumed in the 'daylight' and 'nightly' p eriods of day, respectively. The percentage of nightly feeding activity sig nificantly decreased in the second part of the growth period. There were no ticeable batch (season) and group size effects on most feed intake pattern traits but not on feed intake level. The latter trait showed a markedly low er repeatability across the three stages of growth (around 0.30) than the o ther feeding behaviour traits (0.50-0.60). This study confirms that the fee d intake pattern of growing pigs is influenced by genetic and environmental effects and, to a lesser extent, by genotype x environment interaction eff ects. ((C) Elsevier / Inra).