Cardiovascular and pulmonary effects of romifidine and butorphanol combination in horses - Machado, Thaís Sodré de Lima; Cortopassi, Silvia Renata Gaido; Fantoni, Denise Tabacchi; Cruz, Rodrigo Silvério Ferreira da; Silva, Luis Claudio Lopes Correia da (Brazilian Journal of Veterinary Research and Animal Science, 2006)