While butorphanol is the most commonly used opioid in horses, methadone is not licensed in most countries. Our aim was to compare the effects of both drugs, combined with romifidine, regarding the quality of sedation and induction in horses undergoing elective surgery. Results indicate the suitability of both methadone and butorphanol in this patient population. Animals were scored 10 min after intravenous injection of sedatives. Despite lower overall sedation (OS) score in horses receiving methadone (p = 0.002), the quality and time of induction and intubation remained unchanged. None of the horses had the lowest OS score (no sedation), nor the highest score for ataxia (horse falling). Methadone induced a tendency for minor noise reaction yet minor head lowering scores, the latter being probably the most influencing parameter when scoring OS. Measured physiological parameters decreased in both groups, with greater bradycardia recorded after methadone (p = 0.017), including a higher incidence of atrioventricular blocks that resolved during general anaesthesia. The quality of induction was good–excellent in most of the animals. While comparisons between the degree of antinociception were beyond the scope of this study, analgesic potency might influence the choice when considering opioids as pre-anaesthetic drugs in combination with romifidine before surgery in equines.

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Objectives The aim of this study was to compare the quality of sedation with three different anaesthetic protocols (alfaxalone combined with butorphanol, methadone or pethidine) administered intramuscularly in cats, and to evaluate the influence of the injection site (between supraspinatus and quadriceps muscles) on the onset and quality of sedation. Methods A total of 151 cats were selected for this study. Cats were sedated with alfaxalone (3 mg/kg) combined with either butorphanol (0.3 mg/kg; n = 50), methadone (0.3 mg/kg; n = 53) or pethidine (5 mg/kg; n = 48). The combination was injected intramuscularly into the supraspinatus (n = 79) or quadriceps muscle (n = 72). The data included a scoring system for the quality of sedation and physiological parameters, such as heart rate (HR), respiratory rate, body temperature and occurrence of mydriasis, monitored during the first 30 mins of anaesthesia. Results The opioid associated with alfaxalone influenced the overall sedation score, the degree of myorelaxation, the occurrence of mydriasis and HR. The overall sedation score was poorer with butorphanol than with methadone ( P = 0.008), and butorphanol induced a lower degree of myorelaxation than methadone ( P = 0.013). The injection into the supraspinatus showed better qualitative results for sedation and a faster onset time (in about 3 mins) than that into the quadriceps ( P <0.001). HR decreased from baseline ( P <0.001) and over time ( P <0.001), mainly in cats of the butorphanol–supraspinatus and pethidine–quadriceps groups ( P = 0.004). The occurrence of mydriasis was lower after butorphanol than after methadone and pethidine ( P = 0.025), while the incidence of side effects did not differ among groups. Conclusions and relevance All three protocols provided a good quality of sedation and allowed performing the scheduled procedure. Moreover, the injection into the supraspinatus muscle showed superior results in all the qualitative scores of sedation and quicker onset time than that into the quadriceps muscle.

Invertebrates are a broad group of animals that includes more than 90% of the estimated 10 million species in the world. Some species are abundantly used by man in scientific research and for human consumption. However, the current legislation is still very lacking about the protection toward conditions of pain, suffering, distress or lasting harm that these animals may suffer as a result of experimental practices, fishing and cooking. The purpose of this paper is to summarize what has already been stated by other Authors regarding the possibility that invertebrates (with a specific emphasis on cephalopods) can experience pain and suffering. The results of studies that show the existence, in these animals, of a number of elements that can be associated with the ability to feel pain and not only nociception are highlighted. Objective indicators (such as changes in physiological parameters) and behavioral attitudes of cephalopods that might be related to pain will be addressed as well.