Evaluation of segmental dorsolumbar epidural analgesia with ketamine hydrochloride administered by use of nonstyletted multiple-port catheters via the caudal approach in cattle

To evaluate use of nonstyletted multiple-port catheters for epidural administration of ketamine hydrochloride via the caudal approach to induce analgesia of the paralumbar fossa (flank) in cattle. 6 healthy bulls. 1 week before experiments began, a multiple-port catheter was inserted by use of a Tuohy needle in all cattle via the caudal approach (between the first and second coccygeal vertebrae); the tip was threaded approximately 48 cm cranial into the dorsolumbar region. Each bull was administered ketamine (0.3, 0.5, or 0.7 mg/kg) at time 0. Heart rate, blood pressures, respiratory rate, rectal temperature, analgesia, sedation, and ataxia were determined before treatment (baseline [time 0]); at 5, 10, 15, 30, 45, 60, 75, and 90 minutes; and every 30 minutes thereafter until end of analgesia. All multiple-port catheters were threaded with negligible resistance into the dorsolumbar region in all bulls. All doses of ketamine were effective for inducing analgesia of the flank region of bulls in a standing position. Total analgesia time was dose dependent (35, 50, and 80 minutes for 0.3, 0.5, and 0.7 mg/kg, respectively). All doses of ketamine induced mild or moderate ataxia. Heart rate changes were within acceptable limits. Segmental dorsolumbar epidural analgesia with ketamine administered via multiple-port catheters by use of the caudal approach in cattle was feasible, and the cattle remained standing with minimal adverse effects. Further studies are necessary to determine whether this technique provides optimal conditions to allow surgery in standing cattle.