1. Department of Animal Science and Aquaculture, Dalhousie University, Truro, Nova Scotia, Canada
2. Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada
3. Semex Alliance, Guelph, Ontario, Canada
4. Livestock Gentec, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada