Histogram of the mean peak, plasma cortisol values in lambs less than a week of age, after different methods of rubber ring applications

(Molony et al 2002: Molony & Kent 1997)

Note that there were no significant differences in the peak plasma cortisol of the three most severe treatments (Unilateral castration - 165 nmol/l, bilateral castration without - 172 nmol/l and with tail docking -165 nmol/l).  Short scrotum castration without (98 nmol/l) and with local anaesthetic (42 nmol/l) had significantly lower increases in value.  Cortisol values increased in control lambs by 25 nmol/l, which was not significantly different to the rise in lambs short-scrotum castrated with local anaesthetic (42 nmol/l).