GENETIC-PARAMETERS OF FEEDING-BEHAVIOR AND PERFORMANCE TRAITS IN GROUP-HOUSED LARGE WHITE AND FRENCH LANDRACE GROWING PIGS

Data on feeding behaviour of 3 710 group-housed and ad libitum fed gro wing pigs were recorded using 'Acema 48' electronic feed dispensers. G enetic parameters for six feeding behaviour criteria and the main prod uction traits routinely recorded in French central test stations (thre e 'boar' traits and three 'sib' traits) were estimated in two breeds ( Large White and French Landrace) using a multiple trait animal model D F-REML procedure. Heritability estimates for feeding behaviour criteri a ranged from 0.36 to 0.54 and were markedly higher than that for the food conversion ratio (0.20). Heritability of daily feed intake was 0. 42 in both breeds, whereas heritabilities of rate of feed intake, feed intake per meal and time per meal were slightly higher (0.45-0.54). D aily feed intake showed a very close genetic correlation (around 0.85) with average daily gain but also unfavourable genetic correlations wi th ultrasonic backfat thickness (around 0.5) and lean percentage (arou nd -0.4). Daily feed intake was genetically independent of food conver sion ratio, whereas average daily gain showed a favourable genetic cor relation (around -0.35) with that trait. Among the feeding behaviour c riteria, feed intake per meal and rate of feed intake showed the highe st genetic correlations with daily feed intake (around 0.5) and averag e daily gain (around 0.4). They also showed moderately unfavourable ge netic correlations with ultrasonic backfat thickness (around 0.25) and carcass lean percentage (around -0.25) and seemed to be genetically i ndependent of food conversion ratio. The value of including a trait re lating to feed intake pattern among traits selected for is discussed o n the basis of this set of genetic parameters.