Pain assessment and analgesia following surgical castration in bull calves

Summary

Cattle on pastoral lands are subjected to potentially painful husbandry techniques. This usually occurs once a year after the muster and these procedures are often performed on animals that are older than six months of age. It is seldom that any pain mitigating medications are employed at this time and there is increasing concern that this perceived impost on the animal's welfare will become more significant at both an economic and social level. 
There is a need to investigate the possibility of using simple, cost-effective, readily available medications, administered using relatively quick and easily taught techniques. Providing evidence that not only are these techniques effective in minimising pain and stress but that they are relatively inexpensive and practical will increase the chances of the industry adopting the use of these medications. Investigation of the impact of analgesia and anaesthesia on the welfare of animals post-surgery has been extensive in the past but as yet pain assessment in older, Bos indicus cattle has not been adequately addressed. 
This research used castration as the test model because it is arguably one of the most common and most painful procedures endured by the animals. Station cattle tend to be unhandled and unused to human contact, making the measuring of pain and post-surgical welfare particularly challenging. To best facilitate the detection of treatment differences, a host of parameters were used in this work. This included composite behavioural scores, qualitative behavioural analysis (QBA), periodic measures of live weight, blood cortisol concentrations, balk score, crush score, and nociceptive threshold testing. Additionally, pedometers were fitted to individuals in order to measure activity, number of periods of rest and the duration of those rest periods.