Effects of tail docking and castration on behaviour and plasma cortisol concentrations in young lambs.

Behavioural and cortisol responses of lambs to the usual husbandry practices of castration and, or, tail docking using tight rubber rings were investigated between birth and seven days old. There were four treatments: control handling and blood sampling (n = 52), tail-docking (T) (n = 57), castration plus tail-docking (CT) (n = 54) and intravenous adrenocorticotrophin injection (ACTH) (n = 52). After treatment there was a transient rise in plasma cortisol concentration, the magnitude and duration of which increased in the following order; control, T, CT and ACTH. Behavioural characteristics indicative of distress included restlessness (standing up and lying down frequently, rolling, kicking, stamping), lateral recumbency, immobility with neck extension and hyperventilation. Using changes in cortisol concentrations and behaviour the lamb responses were characterised as reflecting 'mild disturbance without distress' (control, ACTH), 'mild distress' (T) and 'marked distress' (CT). The mild distress lasted for about 30 minutes in T lambs and marked distress for about 60 minutes in CT lambs.