Inmovilización del ganado vacuno mediante la administración de una combinación concentrada fenciclidinas y agonistas de los receptores adrenérgicos α 2

Abstract

The immobilization and anaesthesia of free-range cattle requires the administration of drugs in a small volume with a rifle or dart. The aim of this study was to determine the effects of a concentrated combination of tiletamine-zolazepam (TZ), ketamine (K) and detomidine (D) (TZKD) to immobilize/anaesthetize calves and free-range cattle.In a first study with calves, six healthy males were enrolled in a prospective, randomized, controlled study in which the animals were administered three different doses of TZKD (low, medium and high doses) or saline intramuscularly. Onset and duration of anaesthesia were recorded, as well as basic cardiovascular and respiratory data. Also, two noxious stimuli were applied after TZKD to assess the analgesia. In an observational study in free-range cattle the low dose of TZKD from the previous study was administered intramuscularly (n=53 animals) to immobilize/anaesthetise the animal for clinical procedures. The animals were antagonized with atipamezol once the procedures were accomplished. Anaesthetic onset and anaesthetic and recovery times were recorded.In calves, the TZKD combination produced a dose-dependent anaesthetic action associated with respiratory depression and moderate hypoxemia. Induction time lasted from 6±2 to 4±1 minutes (low and high doses, respectively) and the total recumbency time ranged between one and two hours (low dose and medium and high doses, respectively). In the observational study with free-range cattle, the TZKD combination produced an immobilization suitable to carry out minor surgical procedures or medical treatments. Anaesthetic induction times were similar to those in calves (6±3 min). The duration of anaesthesia depended on the time of administration of atipamezol and animals recovered the standing position 13±9 minutes after administration of the antagonist.In conclusion, TZKD induces a dose-dependent anaesthetic effect in calves associated with moderate respiratory depression. This TZKD combination may be employed not only for immobilization, but also for minor surgical procedures in free-range cattle.