[Behavioural and physiological indicators of pain and distress in calves following tail docking]

According to the German law on animal welfare (§ 6, section 3, No. 3), the prophylactic amputation of beef calves' tail end using elastic rubber rings requires authorities' permission. Removal of the tail end is performed in order to avoid tail tip necrosis. Other invasive management procedures such as dehorning and castration are associated with pain reactions and stress in calves. Also, more proximal docking of the tail between 2 vertebrae has a proven impact on the animal's wellbeing. However, little is known concerning the occurrence of pain and stress during docking the soft tail tip in beef calves. For this reason, this pilot study aimed to evaluate pain reactions of calves during tail docking using rubber rings.

Sixteen male Fleckvieh and Fleckvieh-crossbreed calves 8-10 weeks of age were involved using a double-blind study. On day 0, a rubber ring was placed 3 cm proximally to the tip of the tail in the calves in group A (amputation), whereas calves in the group K (control) underwent a similar control handling. Following the procedure, blood plasma concentrations of cortisol and substance P were determined by ELISA. Parameters concerning behavior and activity were collected using video-assisted observation and recording of pedometer data.

Treatment had no impact on substance P levels. The development of serum cortisol levels showed a decrease in group K compared to baseline values whereas cortisol levels remained constant in group A. On day 0, calves in group A exhibited higher step counts, tail shaking frequency as well as grooming of tail and hind quarters than calves in group K.

Increased step count may be interpreted as restlessness. Frequent tail shaking as well as repetitive tail and rear quarter grooming may be associated with unpleasant sensation of the rubber rings' pressure. Alterations in physiological behavior, as well as a constant level of cortisol on day 0 and day + 1 may be indicative for pain perception provoked by the rubber ring application.

In the first place, improvement of animal welfare is warranted for a reduction in incidence of tail tip necrosis, especially taking husbandry conditions into account. However, if tail docking is deemed necessary, based on the presented results the administration of a non-steroidal anti-inflammatory drug is recommended in order to reduce peri-procedural pain.