The efficacy of
ketamine and
bupivacaine in enhancing the
epidural analgesia induced by
medetomidine was evaluated in 10 buffalo calves utilized repeatedly after a gap of 10 days so that each
drug combination was tested in 4 randomly selected animals. In group A,
medetomidine (15 microg/kg), in group B
ketamine (2.0 mg/kg), in group C
bupivacaine (0.125 mg/kg), in group D
medetomidine and
ketamine (15 microg/kg and 2.0 mg/kg), and in group E
medetomidine and
bupivacaine (15 microg/kg and 0.125 mg/kg) was administered epidurally. Onset of
analgesia was significantly earlier in animals of groups B and D compared to the animals of groups A, C and E.
Medetomidine alone or in combination with
ketamine/
bupivacaine produced complete
analgesia of the tail, perineum, inguinal region and upper parts of hind limbs.
Ketamine produced a very short duration of complete
analgesia at the tail and perineum.
Bupivacaine alone produced only mild to moderate
analgesia. Both
ketamine and
bupivacaine prolonged the duration of
analgesia. Motor
incoordination was mild to moderate in animals of all the groups, but animals remained standing throughout the period of observation. Animals of groups A, D and E showed mild to
moderate sedation during the observation period. Ruminal movements decreased nonsignificantly in animals of groups A and E. Mild salivation was observed in animals of all the groups except group C. Significant decrease in heart rate (HR) was recorded after epidural administration of
medetomidine or
bupivacaine; however,
ketamine caused short duration of
tachycardia. The administration of
ketamine with
medetomidine caused lesser decrease in HR compared to
medetomidine alone or in combination with
bupivacaine. Significant fall in respiratory rate (RR) was recorded after epidural administration of
medetomidine or
bupivacaine alone, but an increase in RR was recorded after
ketamine administration. The fall in RR was less pronounced in animals in which
medetomidine was used with
ketamine compared to the animals in which
medetomidine was used alone or in combination with
bupivacaine. Mean arterial pressure (MAP) decreased and central venous pressure (CVP) increased significantly after epidural administration of
medetomidine in combination with
ketamine or
bupivacaine. The ECG changes included tall T wave, QS pattern, RS pattern and ST elevation and
heart blocks at different intervals, which were more frequent and pronounced in animals given
bupivacaine with
medetomidine. It can be concluded that epidural administration of
medetomidine can produce complete
analgesia of the tail, perineum, inguinal region and upper hind limbs in buffaloes. However, significant depression of cardiovascular parameters was recorded. Administration of
ketamine along with
medetomidine resulted in significantly early onset and slightly longer duration of
analgesia with lesser cardiopulmonary side-effects compared to
medetomidine alone or
medetomidine with
bupivacaine. Addition of
ketamine to
medetomidine thus seems to be useful for producing
epidural analgesia; however, addition of
bupivacaine failed to provide any advantage over
medetomidine alone.