Analgesic effect of caudal epidural ketamine in cattle.

This study was performed to clarify the analgesic effect of ketamine injected into the first intercoccygeal (Co1-Co2) epidural space in standing cattle. Five adult cows were randomly received 3 treatments at least 1 week interval: 5, 10 and 20 mL of 5% ketamine. Sedation, analgesia, ataxia and other effects on cardiopulmonary and rumen functions were assessed before ketamine administration and until 120 min. The analgesia without sedation was shown at tail and perineum about 5 min after all three treatments. The duration of analgesia was significantly increased according to the volume of ketamine (p<0.01). There was a similar tendency of ataxia with individual variation. There were minimal effects on cardiopulmonary and rumen functions. The present study showed that caudal epidural ketamine administration induced analgesia without sedation in cows, and the duration of analgesia was dose dependent with ataxia. However, the duration of analgesia after 5 and 10 mL ketamine administration is short for common surgical procedures and pain relief of perineum. Further studies are needed to prolong the duration of analgesia without side effects.