Anaesthetics for general anaesthesia in growing pigs

A comparison was made between different anaesthetics for general anaesthesia in growing pigs, with focus on minor surgery under field conditions and for experiments in clinical research. Healthy cross-breed pigs (Hampshire x Yorkshire x Swedish Landrace) weighing 20-45 kg were used. The anaesthetics combinations compared were 1) azaperone plus metomidate (AM), 2) Zoletil (zolazepam + tiletamine) plus xylazine (ZX), and 3) Zoletil plus xylazine plus ketamine (ZXK). Parameters measured were: heart rate, respiratory rate, blood pressure, body temperature, and depth of analgesia (pin-prick). Minor surgery was performed to test the reliability of the "pin-prick" tests. It was clearly shown that AM produces anaesthesia with good cardiovascular stability and is a drug combination that is suitable for minor surgery. ZX also produces a good anaesthesia characterized by reliable and rapid induction. Good cardiovascular function is maintained, and the laryngeal relaxation makes intubation possible. These characteristics are very useful in a laboratory environment, as easy handling to avoid stress is necessary for research. Although it is difficult to evaluate the quality of analgesia from this study, it is concluded that ZX did not provide a superior anaesthesia and analgesia compared to AM in crossbreed pigs. However, these drugs are too expensive for regular use in ambulatory practice. The effects of ZXK resemble those of ZX, but the ZXK-drug combination has no anaesthetic advantages and is more laborious to work with.