Comparison of alternative disbudding methods with hot-iron dehorning of goat kids

Abstract

Goat kids are frequently disbudded in intensively farmed units to reduce the number of accidental injuries to other animals and farm workers due to horn growth. The most commonly used method is thermal disbudding which is increasingly causing animal welfare concerns. Therefore the objective of the present study was to evaluate alternative disbudding methods either by injecting clove oil or its synthetic analogue isoeugenol.In this study 40 male Saanen goat kids aged between one and five days were treated using 4 different methods (n = 10 each): injection of 0.2 mL clove oil, 0.2 mL isoeugenol, 0.2 mL isotonic NaCl solution and thermal disbudding. For thermal disbudding general anesthesia was performed. Horn growth of all goat kids was measured. Computer tomography (CT) of the horn bud region and histological examination of biopsy samples taken from the horn bud region were performed. Additionally, saliva cortisol concentrations were measured.Highest success rate was reached with thermal disbudding and disbudding with isoeugenol followed clove oil. Scurs growth after disbudding appeared in 11 horn buds (4 thermal disbudding, 4 clove oil, 3 isoeugenol). CT images of animals after thermal disbudding showed complete destruction of the horn buds but also damage to the frontal bones. CT images of animals after clove oil or isoeugenol injection demonstrated partial destruction or malformation of the horn buds. Purulent osteomyelitis was detected after thermal disbudding (n = 2) and clove oil treatment (n = 1). Histological examination of biopsy sample showed different changes of skin, dermis and epidermis. A significant difference of between the cortisol concentrations before treatment and 10 minutes after treatment was only found in the isoeugenol group (P = 0.015). In the other groups, the increase was not significant. Likewise, only the isoeugenol group showed significantly higher cortisol concentrations (p=0.019) following treatment in comparison with the control group (NaCl).Highest efficacy was reached with thermal disbudding and with isoeugenol followed by clove oil. Disbudding goat kids with isoeugenol caused less tissue damage than thermal disbudding. Injection of clove oil or isoeugenol may therefore be considered as an alternative to thermal disbudding. Future research is required to evaluate the behavioral responses of goat kids to these methods of disbudding. In addition, more research is needed to optimize the injection technique and to validate the growth of scurs after disbudding in goat kids.