Effect of food intake capacity on production traits in growing pigs with restricted feeding

Abstract

ABSTRACTEffects of food intake (FI) and ad libitum food intake capacity (FIC) were investigated in 438 pigs fed in seven batches. Batches 1 to 6 consisted of barrows and batch 7 of gilts. Restrictedly fed animals had one to three ad libitum fed litter mates. In batches 6 and 7, animals were fed ad libitum until 48 kg live weight. Thereafter, two-thirds of the animals were fed according to a fixed weight scale. FIC is considered as a trait of the animal, independent of its actual FI. With ad libitum feeding FIC can be measured directly, with restricted feeding FIC has to be estimated.Two methods of estimating average FIC from about 27 to 107 kg live weight were applied. The first method consisted of assigning to each restrictedly fed animal the average FI of one to three ad libitum fed litter mates. The second method was applied in batches 6 and 7 only and consisted of estimating FIC with multiple regression based on individual 'ad libitum performance' in the first part of the growing period.Effects of FI and FIC on daily gain, food conversion ratio, backfat thickness, lean tissue proportion, fatty tissue proportion, lean tissue growth rate, fatty tissue growth rate and lean tissue food conversion were investigated. FI had significant effects on each trait, except on lean tissue food conversion. FIC had significant effects on body composition traits, but not on daily gain and food conversion ratio.Irrespective of the method used to estimate FIC, results showed that animals with a higher FIC produced more fat and less lean from the same amount of food than animals with a lower FIC. It was suggested that the partition of food energy between energy for maintenance, protein deposition and fat deposition is associated with FIC. The findings confirmed that selection for leaner and more efficient pigs may result in animals with lower FIC, irrespective of the feeding regimen during performance testing.