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The effects of xylazine sedation in 2- to 6-wk-old calves disbudded with a cautery iron.

C. N. Reedman




The effects of xylazine sedation in 2- to 6-wk-old calves disbudded with a cautery iron.
C. N. Reedman*1, T. F. Duffield1, T. J. DeVries2, K. D. Lissemore1, C. B. Winder1. 1Department of Population Medicine, University of Guelph Guelph, ON, Canada, 2Department of Animal Biosciences, University of Guelph Guelph, ON, Canada.

The use of local anesthesia and nonsteroidal anti-inflammatory drug (NSAID) analgesia can reduce indicators of pain and inflammation and support self-rewarding behaviors in calves following disbudding. Although the use of sedation may be recommended as best practice for disbudding, there is little research in this area. The objective of this study was to evaluate the effects of xylazine sedation given with a local anesthetic and NSAID in calves following cautery disbudding. Outcomes included automated feeder parameters, pressure sensitivity (measured by a pressure force algometer) and struggle behavior (by blinded observer). One hundred and 22 female and male Holstein calves aged 13 to 44 d were enrolled over 9 blocks and randomly allocated to 1 of 2 treatments: 1) sedated: lidocaine cornual nerve block, meloxicam and xylazine, or 2) non-sedated: lidocaine cornual nerve block and meloxicam. Data were analyzed using mixed models with a fixed effect for baseline values and a random effect for trial block. Linear regression was used to assess continuous outcomes and logistic regression to assess binary outcomes. Sedated calves had reduced average drinking speed at 0 to 24 h and 24 to 48 h following disbudding compared with non-sedated calves (24 to 48 h; −40.9 mL/min, 95% CI −76.8 to −4.9, P = 0.03) but there was no difference between groups in total amount of milk consumed daily (P = 0.86). Sedated calves had reduced pressure sensitivity (P < 0.01) at 0, 60- and 240-min post-disbudding (0 min; −0.37 kgf, 95% CI −0.49 to −0.25; 60 min; −0.69 kgf, 95% CI −1.03 to −0.35; 240 min; −0.72 kgf, 95% CI −1.16 to −0.28) but there were no detected differences between groups 24 h after disbudding (P = 0.42). During the disbudding procedure, non-sedated calves had 4.5 (95% CI 1.5 to 13.2, P = 0.006) times the odds of struggling more than twice compared with sedated calves. The results indicate that xylazine sedation, in conjunction with a local anesthetic and NSAID, can reduce behavioral indicators of pain in calves disbudded with a cautery iron, but also appears to impact suckling behavior for at least 48 h following sedation.

Keywords: dairy calf, disbudding, behavior.

Biography: Cassandra Reedman is a PhD student in the Department of Population Medicine at the University of Guelph studying epidemiology focusing on pain control strategies for disbudding calves. She has a BSc in Animal Biology from the University of Guelph and began graduate school in May 2018 starting in an MSc program and recently transferred to a PhD in the Fall of 2019. So far in her research she has completed 2 clinical trials assessing pain control for different methods of disbudding in young calves and is currently conducting the third trial of her research.