Objectives The overall aim of the proposed research is to explore the benefits of closely meeting the changing nutrient requirements of individual sows during gestation and across parities, in a group housing system and using computer controlled electronic sow feeders. Specific objectives are to determine the effect of meeting the estimated nutrient requirements of individual (parity 1, 2 or 3) sows on: 1.Sow welfare and reproductive performance: sow behaviour, injuries and health, litter size at birth, mean and average piglet weight at birth and weaning, sow feed intake and body weight changes during lactation, weaning to breeding interval, subsequent litter size, 2.Quality of offspring: robustness (susceptibility to a pathogen challenge), growth performance, feed efficiency and carcass quality, and 3.Estimated nitrogen, phosphorus and carbon balance during gestation and lactation and margin over feed costs. Submission Number: UofG2013-1722 Funding Program: OMAFRA / UofG Partnership - Research Keywords: gestating sows, electronic feeding, performance Theme: Production Systems - Animal Commodity/Sector: Animal Production