RELATIONS AMONG INDIVIDUAL (RESIDUAL) FEED-INTAKE, GROWTH-PERFORMANCEAND FEED-INTAKE PATTERN OF GROWING PIGS IN-GROUP HOUSING

Individual daily feed intake (FID) and feed intake pattern were record ed on a total of 405 group housed growing pigs, divided over five batc hes. Residual feed intake (RFID) was defined as FID adjusted for predi cted feed intake (pFID) based on metabolic body weight (MBW) and perfo rmance level (body weight pin and lean percentage in the carcass). RFI D is a measure of feed use per kg pin at a certain level of metabolic body weight and lean percentage. Variation in pFID accounted for 22% o f the variation in FID. In this study RFID was used as a trait to meas ure individual variation in non-accounted energy costs. Correlations b etween RFID and feed intake pattern traits were calculated to determin e the effect of feed intake activity on variation in gross energy util isation. Correlations of RFID with daily eating time and eating freque ncy were significantly positive. The relationships indicated that the pigs with a lower RFID had less meals, with visits to the feed hopper more spread out over the day, and they spent less time eating per day. Furthermore, these pigs showed a slightly higher feed intake per visi t. Variation in feed intake activity, described by number of visits pe r day and daily eating time, accounted for 44% of the variation in RFI D. Pigs with a higher pFID were pigs with a higher growth performance level. There were no clear correlations between pFID and eating freque ncy or duration, but pigs with a higher pFID had a higher rate of feed intake and a higher feed intake per visit and per meal. It is conclud ed that a low RFID (in this study lower maintenance requirements per k g metabolic body weight), is associated with a short daily eating time and a low eating frequency.