1. Centre for Nutrition Modelling, Department of Animal & Poultry Science, University of Guelph, Guelph ON, Canada N1G 2W1
2. Instituto de Ganadería de Montaña (CSIC-ULE), Departamento de Producción Animal, Universidad de León, 24071 León, Spain
3. Procter & Gamble Pet Care, 8700 Mason Montgomery Road, Mason, OH 45040, USA