LAUSR

I read with interest the paper by Rees et al. [1]. In particular, I was concerned regarding the lack of information related to the anaesthesia and treatment of the animals. It would appear that the authors had not taken advice from veterinary anaesthetists, which should have been readily available in their city, on general anaesthesia in sheep and on the anatomy of the larynx and trachea in sheep. Initial training could well have been provided on ‘thoracic plucks’ of sheep which are readily available from abattoirs. Reference is made to minimum alveolr concentration (MAC) 4, which is somewhat confusing. The published MAC figure for sheep is mean (SD) 1.42 (0.19)% [2].The authors chose to use nitrous oxide which has a MAC greater than 100% and is rarely, if ever, used in anaesthesia of ruminants (sheep) as it rapidly diffuses into the rumen and produces respiratory compromise. There is no mention of the circuit which was used to administer the inhalational agents. Of greater concern, no mention is made of any analgesic agent being administered to the sheep. Finally it must be assumed that the sheep were euthanised, but there is no mention of this or of the technique used.