Current commercial gestation sow feeding strategies do not consider the sow as an individual; they are generally based on using a single gestation diet for all sows regardless of parity or stage of gestation. Computer controlled electronic sow feeders (ESF) allow precision feeding (PF) of individual, gestating sows housed in groups. This thesis evaluated the effects of PF primiparous sows using the NRC (2012) nutrient requirement model, on sow body weight (BW) and back fat (BF) changes during gestation, animal well-being, lactation performance and environmental impact. A performance trial demonstrated ESF technology using blended feeding of two basal diets to meet the unique energy and lysine requirements of individual sows in a group housing system is possible. In this study, PF of sows did not affect overall gestation BW and BF gain, sow feeding behaviour, lactation performance or nutrient balances. However, patterns of BW gain for PF sows more closely reflected the gains of fetus and reproductive tissues which could have effects on long term sow performance.