Towards a Better Understanding of the Effects of Current Pain Mitigation Practices and Potential Avenues of Change for the Disbudding of Dairy Calves
This thesis was an exploration of current disbudding and dehorning practices for dairy calves, and an examination of potential refinements for both technical practices and extension efforts. A systematic review was conducted to synthesize the scientific literature with regard to the effects of local anesthesia and/or analgesia on several outcomes associated with the pain caused by cautery disbudding. A cross-sectional survey of dairy producers and bovine veterinarians in Ontario, similar to one done 10 years ago, was conducted to investigate current methods and management factors associated with adoption of best practices for pain control. The efficacy of an online training module designed to teach proper cautery disbudding technique, including administration of a cornual nerve block, was tested on both veterinary students and dairy producers. Finally, the effect of two local anesthetic protocols on outcomes related to pain associated with caustic paste disbudding were studied. The systematic review and meta-analyses showed evidence for best practices to include use of local anesthesia and NSAID. It also revealed challenges in the combinability of behavioural measures between studies, as compared to more standardized outcomes such as plasma cortisol. Heterogeneity present in some analyses, including several pertaining to pain behaviour, may reflect many differences between studies, including how behavioural measurements were obtained in each study as well as the number of NSAID products tested in the literature. Findings from the 2014 survey showed improvements in the adoption of pain control by both veterinarians and dairy producers since 2004, although more work is needed to reach full adoption by both populations. Veterinary involvement on farm was associated with use of pain control, but exploration of non-use of NSAID revealed a disconnect between veterinarians and dairy producers on the influence of cost. Both veterinary students and practitioners were surprisingly successful on evaluation after training solely via the online module, as compared to a hands-on training group. However, small differences in technical skill and confidence were seen. A combined approach appeared to work well with dairy producers. Online training may be a useful resource in addition to hands-on training, or as a stand-alone if hands-on training is not available. Caustic paste was shown to be acutely painful for at least 3 h after application, but this was reduced by the use of a lidocaine cornual nerve block in addition to meloxicam. A novel concoction of caustic paste containing local anesthetic agents was not effective. We recommend use of a cornual nerve block in addition of an NSAID for caustic paste disbudding.