[1] Univ Liverpool, Dept Livestock & One Hlth, Inst Infect Vet & Ecol Sci, Liverpool CH64 7TE, Merseyside, England
[2] Univ Liverpool, Inst Infect Vet & Ecol Sci, Sch Vet Sci, Liverpool CH64 7TE, Merseyside, England
[3] Univ Liverpool, Inst Populat Hlth, Liverpool L69 3GL, Merseyside, England
[4] World Horse Welf, Anne Colvin House, Norwich NR16 2LR, Norfolk, England
[5] British Horse Soc, Welf Dept, Abbey Pk, Stareton CV8 2XZ, Warwick, England
[6] Horse Trust, Slad Ln, Princes Risborough HP27 0PP, England