Development of the Horse Grimace Scale (HGS) as a Pain Assessment Tool in Horses Undergoing Routine Castration Dalla Costa, Emanuela ; Minero, Michela ; Lebelt, Dirk ; Stucke, Diana ; Canali, Elisabetta ; Leach, Matthew C. Abstract Publication: PLoS ONE Pub Date: March 2014 DOI: 10.1371/journal.pone.0092281 Bibcode: 2014PLoSO...992281D