Clinicophysiological and haemodynamic effects of fentanyl with xylazine, medetomidine and dexmedetomidine in isoflurane-anaesthetised water buffaloes (Bubalus bubalis)

Developments in buffalo anaesthesia with special reference to diaphragmatic herniorrhaphy

Ruminants are poor subject for general anaesthesia. Diaphragmatic hernia (DH) is a common digestive disorder in buffaloes requiring balanced general anaesthesia for surgical repair. For premedication, initially, a combination of phenothiazine/chloralhydrate was used which was later replaced by alpha2 agonist like xylazine. Anticholinergics like atropine or glycopyrrolate were included in balanced anaesthetic protocols to reduce cardiac depression by alpha2 agonists. Thiobarbiturates historically were used for induction and maintenance but late recovery and cardiorepiratory depression lead to switch over to propofol. Maintenance of anaesthesia by top-up or continuous rate infusion (CRI) of propofol was not economical. The inclusion of opioids like butorphanol improved the analgesia as well as has dose sparing effect on induction and maintenance agent. The introduction of inhalants for maintenance significantly improved outcomes with the ease of change of depth of anaesthesia. It has also been observed that adrenocortical suppression by etomidate and mechanical intermittent positive pressure ventilation (IPPV) resulted in poor outcomes whereas maintaining the homeostasis and functional adreno-cortical axis of buffaloes under anaesthesia improves the success rate of DH surgeries. The balanced anaesthetic combination of Atropine/xylazine/ butorphanol/propofol/isoflurane has been found to be most satisfactory till date in buffaloes undergoing DH surgery. The studies on muscle relaxants, blood gas analysis and end tidal carbon dioxide (EtCO2) in buffaloes are scarce. Moreover, many drugs have been used in combinations in clinical cases on the basis of extrapolation from other species; but in buffaloes the effect of individual drug (like dose sparing effect of analgesics, minimum alveolar concentration (MAC) of inhalants) has to be still studied.

The Clinical Effect of Xylazine Premedication in Water Buffalo Calves (Bubalus bubalis) Undergoing Castration under General Anaesthesia

Simple Summary

Castration is used to improve the management of buffalo calves and their meat quality. Despite the growing interest in livestock welfare, water buffaloes have not been studied as frequently as other species. General anaesthesia produces complete unconsciousness, insensitivity to pain and muscle relaxation. The quality and safety of general anaesthesia may be improved using sedatives prior to the induction of general anaesthesia. The aim of this study was to evaluate the effect of two different intramuscular doses of xylazine for premedication, followed by ketamine induction, in water buffalo calves undergoing isoflurane maintenance anaesthesia for routine castration surgery. Based on the results obtained, we can conclude that both protocols are safe for buffalo castration, but the higher dose protocol is recommended for buffalo orchiectomy.

Abstract

Castration is one of the most frequently performed surgical procedures in livestock. All methods of castration are associated with a significant degree of pain, affecting the patients’ welfare. Limited information on species-specific protocols in buffaloes is available. Considering the importance of this species and the scarcity of reports available, the objective of this study was to evaluate the effects of two different intramuscular doses of xylazine for premedication in water buffalo calves undergoing isoflurane maintenance anaesthesia for routine castration surgery. Twenty clinically healthy male water buffaloes undergoing bilateral orchiectomy were randomly assigned to two groups of 10 animals each: Group 1 was premedicated with xylazine 0.1 mg/kg bw i.m. and Group 2 was premedicated with xylazine 0.15 mg/kg bw i.m. Anaesthesia was induced by ketamine (2 mg/kg bw i.v.) and maintained with isoflurane-oxygen-air in both groups. The HR, RR, presence/absence of ataxia, sedation, depth of anaesthesia, muscle relaxation status, response to acoustic and tactile stimuli, eyelid reflex, extent of salivation and stimulus were evaluated every 5 min. Both protocols provided consistent sedation and were safe. Faster and more satisfactory sedation was recorded when xylazine was administered at 0.15 mg/kg bw i.m., leading us to recommend this dose for buffalo orchiectomy.