Disbudding of dairy goat kids: Refining protocols to reduce or eliminate pain

The aim of this thesis was to investigate potential improvements for disbudding dairy goat kids to eliminate or reduce pain. Behavioural and physiological measures were used to evaluate: (1) pain associated with four disbudding methods, and (2) the effect of pain mitigation on cautery disbudded goat kids. Caustic paste and cryosurgical disbudding and clove oil injection initially showed promise as less painful alternatives to cautery disbudding. However, caustic paste and cryosurgical disbudding were found to be more painful, as cortisol concentrations and the frequencies of head-directed behaviours were higher than for cautery disbudded kids. Clove oil injection appeared to cause no more pain than cautery disbudding based on similar cortisol concentrations and head-directed behaviour, but caused less tissue damage. Alternatives to current practices must be efficacious in preventing horn or scur growth, therefore the effect of clove oil injection and two cautery disbudding techniques (horn bud removed vs. left intact) on horn growth were evaluated. Clove oil was ineffective at preventing horns or scurs compared with cautery disbudding. In addition, cautery disbudding by removing the horn bud was more successful at preventing growth than leaving the horn bud intact. As using a cautery iron to remove the horn bud appeared to be the most efficacious method evaluated in this thesis, the effect of isoflurane and meloxicam on pain associated with cautery disbudding was investigated. Goat kids disbudded under isoflurane, with or without meloxicam, had lower cortisol concentrations and displayed fewer head-directed behaviours than goat kids that were cautery disbudded without pain relief, suggesting that isoflurane can reduce pain associated with cautery disbudding. Overall, the results of this thesis suggest that cautery disbudding is an effective practice but should ideally be carried out using isoflurane to reduce pain; also, complete horn bud removal lowers the risk of horn or scur development. These results support the continued use of cautery disbudding by the dairy goat industry but suggest pain relief could significantly improve the welfare of dairy goats on farm.