Vetlife, Centre for Dairy Excellence, Geraldine 7930, New Zealand; Vetlife Temuka, Temuka 7920, New Zealand.
AgResearch, Ruakura Research Centre, Hamilton 3240, New Zealand.
J Dairy Sci. 2019 Mar;102(3):2492-2506. doi: 10.3168/jds.2018-15033. Epub 2019 Jan 11.
Anesthesia of the horn bud for calf disbudding commonly is attained by injection of local anesthetic over branches of the cornual nerve, with anesthesia achieved in 3 to 20 min. With experienced and trained staff, this method is effective in 88 to 100% of calves. Variability in response and time of onset can compromise calf welfare if calves are disbudded before anesthesia is attained. Proposed legislative reliance on effective local anesthetic as the minimal method of pain relief for calves at disbudding means that administration of local anesthetic must achieve a repeatable level and rapid onset of analgesia. We describe an alternative method of local anesthesia administration that uses local site infiltration of anesthetic over the horn bud. However, this method has not yet been scientifically validated. This study assessed differences between disbudding using the cornual nerve block and disbudding with local anesthesia administered by local site infiltration. Efficacy of local anesthesia was assessed at 30-s intervals after administration by absence of reaction to 3 consecutive needle pricks over the horn buds. Behavior indicating pain was assessed during disbudding and scored from 0 to 3. Calf behavior was also recorded for 3 h after disbudding. Accelerometer data loggers were fitted to each calf for 24 h before and after disbudding to assess lying and standing times. Median time to cutaneous desensitization for local infiltration was 60 s compared with 225 s for cornual nerve block, and the variance in time to desensitization was less with local infiltration. Calves disbudded under cornual block had a larger behavioral response (indicated by a graded aversive body reaction) than calves disbudded under local infiltration. A multivariable model predicted that the mean body reaction score would be 0.6 for calves disbudded under local infiltration and 1.2 for calves disbudded under cornual block. There was no difference in any behaviors between the treatment groups in the 3 h after disbudding. Method of analgesia had no effect on lying time over the 24 h after disbudding. In this study, local infiltration was at least as effective in providing analgesia for disbudding as the cornual nerve block. Our results suggest that a more consistent, effective level of analgesia during disbudding was achieved using local infiltration and that there was no difference in postoperative expressions of pain.
给牛角芽麻醉以进行小牛去角通常是通过在角状神经的分支上注射局部麻醉剂来实现的，麻醉在 3 到 20 分钟内生效。对于经验丰富且训练有素的工作人员来说，这种方法在 88%到 100%的小牛中是有效的。如果在达到麻醉效果之前对小牛进行去角，那么反应和起效时间的变化可能会影响小牛的福利。拟议的立法依赖有效的局部麻醉作为去角时小牛的最低限度止痛方法，这意味着局部麻醉的给药必须达到可重复的水平和快速的镇痛作用。我们描述了一种替代的局部麻醉给药方法，即在角芽上局部注射麻醉剂。然而，这种方法尚未经过科学验证。本研究评估了使用角状神经阻滞去角与局部麻醉剂局部注射去角之间的差异。通过在角芽上连续 3 次针刺无反应，30 秒评估一次局部麻醉的效果。在去角过程中评估疼痛行为，并从 0 到 3 进行评分。去角后 3 小时还记录了小牛的行为。在去角前后 24 小时内，为每头小牛配备加速度计数据记录器，以评估躺卧和站立时间。局部浸润的皮肤脱敏中位时间为 60 秒，而角状神经阻滞的中位时间为 225 秒，且局部浸润的脱敏时间方差较小。在角状神经阻滞下进行去角的小牛的行为反应（表现为不愉快的身体反应）比在局部浸润下进行去角的小牛更大。多变量模型预测，在局部浸润下进行去角的小牛的平均身体反应评分将为 0.6，而在角状神经阻滞下进行去角的小牛的平均身体反应评分将为 1.2。去角后 3 小时，两组治疗的任何行为均无差异。在去角后的 24 小时内，镇痛方法对躺卧时间没有影响。在这项研究中，局部浸润在提供去角镇痛方面至少与角状神经阻滞一样有效。我们的结果表明，在局部浸润下，在去角过程中实现了更一致、更有效的镇痛水平，并且术后疼痛表达没有差异。
