Clinical effects of two doses of butorphanol with detomidine for intravenous premedication of healthy warmblood horses

Influence of Butorphanol, Buprenorphine and Levomethadone on Sedation Quality and Postoperative Analgesia in Horses Undergoing Cheek Tooth Extraction

The aim of this prospective clinical trial was to compare the influence of butorphanol, buprenorphine and levomethadone on sedation quality and postoperative analgesia in horses undergoing cheek tooth extraction. Fifty horses were assigned to three groups prior to oral cheek tooth extraction. Horses were treated with acepromazine, followed by a detomidine bolus, one of the three opioids and both a nerve block and gingival anaesthesia. During the surgery, sedation was maintained with a detomidine constant rate infusion. After surgery, the quality of sedation, surgical conditions and severity of the extraction were assessed with a numerical rating scale. To evaluate differences in the quality of analgesia between the three treatments, postoperative pain was estimated with the Equine Utrecht University Scale for Facial Assessment of Pain. Additionally, several parameters that are associated with dental pain were added to this validated pain score, and blood samples were taken to measure serum cortisol. Our analysis showed lower pain scores and a greater analgesic effect with levomethadone and buprenorphine compared with butorphanol, with increased locomotor activity induced by buprenorphine. While cortisol values demonstrated higher response in horses treated with levomethadone and buprenorphine compared to butorphanol, these values could be biased by unrelated stressors.

Analgesic Effect of Butorphanol during Castration in Donkeys under Total Intravenous Anaesthesia

Pain management is necessary for all surgical procedures. Little scientific evidence about drug efficacy in donkeys is available. The aim of this study was to evaluate the analgesic effect of butorphanol in donkeys undergoing orchiectomy under total intravenous anaesthesia with guaifenesin-ketamine-detomidine. A randomized blinded prospective clinical trial (Protocol n. 2021/0000338), was carried out on 18 clinically healthy donkeys undergoing bilateral orchiectomy. Patients were assigned to Group D (n = 8) or Group DB (n = 10) if receiving intravenous detomidine or detomidine-butorphanol respectively, before induction of general anaesthesia with ketamine-diazepam. Intraoperative muscle relaxation, nystagmus, palpebral reflex, heart and respiratory rate, and non-invasive blood pressure were evaluated every 2 min; time to prepare the patient, duration of surgery and anaesthesia and recovery score were recorded. Group D had significantly longer surgical time, higher heart rate, higher systolic and mean blood pressure (p < 0.05; repeated measure ANOVA), increased muscle rigidity and expression of palpebral reflex (p < 0.05; Mann-Whitney U test) than group DB. Top-ups with thiopental were statistically higher in Group D. Butorphanol and detomidine together produced a more stable anaesthetic plan. The low dosage of opioid and alpha-2-agonists and reduced rescue anaesthesia are responsible for a safer and more superficial anaesthesia, which is mandatory under field conditions.