Montbeliard calves were dehorned by applying a caustic preparation (potassium hydroxide) at 4 weeks of age or by heat cauterisation at 8 weeks of age. Behavioural studies, of 84 calves (dehorned by heat or chemical treatment, with and without anaesthesia), were monitored by video or by visual observations. Throughout a 24 h period after disbudding, the ratio of lying to standing was unchanged in all treatment groups. The main behavioural modifications consisted of drastic but transient reduction in rubbing and social behaviours concomitant with an increase in behaviours indicating distress or pain: restlessness (frequent standing up and lying down), repeated shaking of the head or ears and scratching the lesion with the hind foot. All behaviours indicating pain or discomfort disappeared within 4 h. Cortisol assays, performed on 80 calves (different from those used for behavioural studies) showed a peak in plasma cortisol levels (12-18 ng/ml) which was of moderate magnitude when compared with the 40 ng/ml peak shown by 3 animals in response to an i.v. injection of ACTH. It is concluded that calves dehorned without anaesthesia experienced, with both treatments, intense but brief pain and discomfort. Although the comparison between treatments is questionable because of the differences in ages, animals disbudded by heat cauterisation exhibited weaker reactions. Local anaesthesia reduced increases in plasma cortisol in chemically disbudded calves and induced a strong reduction of reactions in 60% of animals with both treatments.
|Publication Title||Applied Animal Behaviour Science|
|Author Address||Centre National d'Etudes Veterinaires et Alimentaires, BP 53 Beausemaine-22440, Ploufragan, France.|
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