The CRC for Beef Genetic Technologies (the 'Beef CRC') has established the Maternal Efficiency Project to provide new knowledge to help better inform beef producers on the impacts estimated breeding values for carcase fatness/carcase muscularity and for feed efficiency have on maternal efficiency, especially under variable nutritional environments. The project is being conducted across southern Australia. It has an industry herd component and a research station component being run simultaneously. Early results from the research stations show that selection for traits affecting body composition holds across seasons and nutrition treatments, and that genetically leaner cows seem to be less fertile, especially under low nutrition. Results are peer-reviewed and compiled for industry dissemination in the Maternal Journal available through the Beef CRC website (www.beefcrc.com.au).