Analgesic combinations to reduce the stress/pain responses in ewes submitted to non-surgical embryo recovery: butorphanol associated with meloxicam or with dipyrone/hyoscine.

The aim of this study was to compare the effectiveness of different analgesic protocols in reducing physiological stress markers in Santa Inês ewes undergoing non-surgical embryo recovery (NSER). In Experiment 1 (n = 32), ewes received a combination of butorphanol and meloxicam, whereas in Experiment 2 (n = 34), animals were treated with butorphanol combined with dipyrone and hyoscine. In Experiment 1, ewes received butorphanol (0.1 mg/kg IM) associated with meloxicam (1 mg/kg IV). In Experiment 2, animals were treated with butorphanol (0.1 mg/kg IM) combined with a dipyrone-hyoscine mixture (5 g dipyrone + 0.04 g hyoscine; 5 mL IM and 5 mL IV). Controls received equivalent volumes of saline. In Experiment 2, dipyrone-hyoscine was re-administered 24 h post-procedure. Ewes were synchronized, superovulated, and subjected to cervical dilation before NSER. Heart rate, respiratory rate, and blood biomarkers were recorded before sedation (BS), after sedation (AS), before cervical transposition (BCT), immediately after collection (IAC), and at 0.5, 1.5, 3, 6, 12, 24, and 48 h after collection (AC). In Experiment 1, respiratory rate was affected by treatment over time, it was greater (P=0.048) in control ewes than in ewes that received butorphanol associated with meloxicam at AS and 0.5hAC. No other variable differed significantly between groups. In Experiment 2, there was an interaction between treatment and time in heart rate. Heart rate was greater in ewes treated with butorphanol combined with a dipyrone-hyoscine mixture than in control ewes (P = 0.001), and there was also a significant interaction between treatment and time (P = 0.001). It was greater in treated ewes than in control ewes at AS, IAC, 0.5hAC, and 1.5hAC. No significant effects were detected for the remaining parameters. Under the tested conditions, neither analgesic protocol significantly reduced physiological indicators of stress.