1 Scotland's Rural College (SRUC), West Mains Road, Edinburgh EH9 3JG, UK; Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Edinburgh EH25 9RG, UK. Electronic address: m.connor@irri.org.
2 Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Edinburgh EH25 9RG, UK.