Dogs received intra-articular injections of saline solution ( 0.2 mL/kg [ 0.09 mL/lb ] ) , morphine ( 0.1 mg/kg [ 0.045 mg/lb ] ) , dexmedetomidine ( 2.5 g/kg [ 1.14 g/lb ] ) , or a combination of morphine ( 0.1 mg/kg ) and dexmedetomidine ( 2.5 g/kg ) .