Randomised, controlled field trial of two new techniques for the castration and tail docking of lambs less than two days of age

摘要

Two methods to reduce the pain associated with the castration and tail docking of lambs with rubber rings were tested by 10 shepherds, each using 60 housed lambs. in 20 of the lambs the innervation to the scrotum, testes and tail was crushed with a 'Big Nipper' bloodless castrator, and in 20 local anaesthetic (2 per cent lignocaine with adrenaline) was injected with a newly developed high-pressure jet injector under the rubber rings after they had been applied; 10 lambs were given a placebo treatment and 10 were treated by the shepherds' routine elastrator ring procedure. Both new methods significantly decreased the incidence of limb and tail movement by 78 per cent and the time spent by the lambs in abnormal postures, when compared with either the shepherds' routine treatment or the placebo treatment. An experienced observer and most of the shepherds also assessed that the lambs suffered signficantly less pain when treated by the two new methods than when they were treated with rubber rings alone. No detrimental long-term effects of the two new methods were observed. on average the new methods took 68 seconds to apply, compared with 29 seconds for the rubber rings; of the two new methods most shepherds preferred using the pressure jet injector.