Dogs were randomly assigned to one of two groups : Group M received maropitant ( 1.0 mg kg ( -1 ) ) and Group S received 0.9 % saline ( 0.1 mL kg ( -1 ) ) intravenously 45-60 minutes before premedication with hydromorphone ( 0.1 mg kg ( -1 ) ) and acepromazine ( 0.03 mg kg ( -1 ) ) intramuscularly .