Epidural administration of ropivacaine or ropivacaine and xylazine in cattle

Abstract

Epidural protocols are commonly used in cattle, enabling surgical procedures with the animal in standing position, however, problems such as paresis and recumbency beyond that, blocking/recovery times are important factors in protocol choice. The aim of this study was to evaluate time and quality of block and systemic effects of two epidural protocols in cattle. Fourteen crossbred cows with 350 ± 170 kg of body weight were located in two groups with 7 animals each: ropivacaine (GR) they received epidural injection of ropivacaine (0.1 mg.kg-1), and ropivacaine/xylazine (GRX) that received ropivacaine and xylazine (0.075 mg.kg-1and 0.05 mg.kg-1 respectively) in the same route. The following parameters were evaluated, heart rate (HR), respiratory rate (RR), mean blood pressure (MBP), ruminal movements (RM), rectal temperature (RT), durations of epidural block (DB), quality of block (QB), response to nociceptive stimulus by clamping perineal region, degree of paresis (DP) and hemogasometric evaluation. They were evaluated until 420 minutes after epidural. HR, pH, RR, PaCO2, Na+, Ca++, HCO3 -and Base Excess (BE) did not differ between groups. It was observed a slight decrease for RM, and an increase for PaO2 and RT in GRX comparing with GR. Both protocols were effective producing a long lasting sensitive block (6 hours in GR, and 7 hours in GRX). In both groups using nociceptive stimuli, the quality of block was considered good/excellent (66% of animals in GR at M360 and 71% of animals in GRX at M420). The animals of GRX showed mild to severe paresis from M15 to M240. We concluded that both protocols can be used by epidural route, and ropivacaine associated with xylazine administered by epidural route presents a longer sensitive block than isolated, but causes paresis as a side effect.

Keywords

• Peridural; Cattle; Local anesthetic; a2 agonists; Local block