Abstract
Background:
Lumbosacral epidural analgesia is one of the most important techniques for sheep anesthesia and is frequently used for surgery in caudal body regions.

Aim:
This study aimed to evaluate the antinociceptive, locomotor, and sedative effects of lumbosacral epidural injection of bupivacaine alone or in conjunction with dexmetatomidine in sheep.

Methods:
Nine clinically healthy mixed-breed sheep were used. Each sheep received either bupivacaine (BUP) alone or bupivacaine in combination with dexmetatomidine (BUP-DEX). The heart rate, heart rhythm, respiratory rate, and rectal temperature were monitored. Anesthetic onset, recumbency duration, and unassisted standing time were recorded. Analgesic, sedative, and locomotor scores were assessed using established numeric scales.

Results:
Analgesia onset was noted after 6.50 ± 2.75 min in the BUP group and after 4.33 ± 0.67 min in the BUP-DEX group. Sheep showed tendency for recumbency in BUP group at 3.33 ± 1.28 min after epidural injection and at 3.00 ± 0.68 min after epidural injection in the BUP-DEX group. Animals tended to stand earlier in the BUP group (199.83 ± 23.55 min) than in the BUP-DEX group (496.00 ± 82.97 min) (p = 0.014). Marked sedation was noted in the BUP-DEX group. Motor block was detected in both groups. The analgesic score was more intense and had a longer duration in BUP-DEX than in BUP. Minimal cardiorespiratory changes were observed in BUP-DEX.

Conclusion:
Briefly, using of bupivacaine-dexmedetomidine mixture for epidural anesthesia is an important technique in sheep subjected to long-term surgical operations in the tail, perineal, inguinal, hind limb, flank, and umbilical regions with sufficient sedation, long-term recumbency, and minimal side effects.

Key words: Bupivacaine, Dexmedetomidine, Epidural anesthesia, Sheep