Objective To evaluate the anti-nociceptive effects of lidocaine, lidocaine-bupivacaine combination or bupivacaine following caudal epidural administration in cows undergoing reproductive procedures.
Study design Blinded, randomized experimental study.
Animals Thirty seven healthy Holstein cows (mean weight ± SD, 633 ± 41 kg).
Methods Animals were allocated randomly to receive one of four treatments: group LID, 0.2 mg kg−1 lidocaine 2%; group LID-BUP, lidocaine-bupivacaine mixture in a 1:1 volume ratio (0.1 mg kg−1 and 0.025 mg kg−1, respectively); group BUP-LD, 0.05 mg kg−1 bupivacaine 0.5%; and group BUP-HD, 0.06 mg kg−1 bupivacaine 0.5%. The onset and duration of perineal anti-nociception were determined using superficial and deep pin pricks and the number of cows with complete perineal anti-nociception was recorded. Parameters were compared using anova followed by Duncan’s test where relevant.
Results Mean ± SD time to onset of anti-nociception following epidural administration of BUP-LD was significantly longer than for LID-BUP (p < 0.05). The duration (in minutes) of perineal anti-nociception was significantly longer following epidural administration of BUP-HD (247 ± 31) versus LID-BUP (181 ± 33) and LID (127 ± 25) minutes respectively. The % of cows with complete anti-nociception was increased in the group treated with BUP-HD compared to BUP-LD. Severe ataxia or recumbency did not occur in any groups.
Conclusions and clinical relevance Epidurally administered bupivacaine, at a dose of 0.06 mg kg−1, may provide satisfactory caudal epidural anti-nociception for longer-duration obstetric and surgical procedures.