1. School of Veterinary Medicine and Science, University of Nottingham; Sutton Bonington Campus Loughborough LE12 5RD UK
2. Ruminant Mineral Consultancy; 39 Stratton Heights Cirencester GL7 2RH UK
3. Inorganic Geochemistry, Centre for Environmental Geochemistry, British Geological Survey; Keyworth Nottinghamshire NG12 5GG UK
4. School of Biosciences, University of Nottingham; Sutton Bonington Campus Loughborough LE12 5RD UK