Chemical restraint and anaesthetic effects of a tiletamine–zolazepam/ketamine/detomidine combination in cattle

The immobilisation and anaesthesia of free-ranging cattle requires the administration of appropriate drugs in small volume via rifle or dart. The objective of this randomised controlled study was to test the capacity of a concentrated combination of tiletamine–zolazepam (TZ), ketamine (K) and detomidine (D) (TZKD) to immobilise/anaesthetise calves. Following administration of low, medium and high doses of TZKD to six healthy animals IM, the time-of-onset and duration of anaesthesia were recorded, in addition to standard cardio-respiratory parameters. Two noxious stimuli were applied to assess the analgesic effect of the combination. TZKD produced a dose-dependent anaesthetic action associated with respiratory depression and moderate hypoxaemia. Total recumbency lasted from 1 h (with low dose) to 2 h (with medium and high doses). The findings indicate that TZKD induces anaesthesia in calves, suitable not only for animal immobilisation, but also to carry out minor surgical procedures with or without additional local analgesia. Respiratory depression was the most severe side-effect and careful patient monitoring is recommended when using this drug combination.