Knauer W A, Barrell E A, Guedes A G P, Ventura B A
Department of Veterinary Population Medicine, University of Minnesota, St. Paul 55108.
Department of Veterinary Population Medicine, University of Minnesota, St. Paul 55108.
J Dairy Sci. 2023 Apr;106(4):2830-2845. doi: 10.3168/jds.2022-22433. Epub 2023 Mar 2.
Dairy goat kids are commonly disbudded in the United States without pain relief. Our objective was to identify an efficient pain management strategy by monitoring changes in plasma biomarkers and behavior of disbudded goat kids. A total of 42 kids (5-18 d old at the time of disbudding) were randomly allocated to 1 of 7 treatments (n = 6/treatment): sham treatment; 0.05 mg/kg i.m. xylazine (X); 4 mg/kg subcutaneous buffered lidocaine (L); 1 mg/kg oral meloxicam (M); xylazine and lidocaine (XL); xylazine and meloxicam (XM); and xylazine, meloxicam, and lidocaine together (XML). Treatments were administered 20 min before disbudding. One trained individual, blinded to treatment, disbudded all kids; sham-treated kids were handled similarly except the iron was cold. Jugular blood samples (3 mL) were obtained before (-20, -10, and -1 min) and after (1, 15, and 30 min, and 1, 2, 4, 6, 12, 24, 36, 48 h) disbudding and analyzed for cortisol and prostaglandin E (PGE). Mechanical nociceptive threshold (MNT) testing was performed at 4, 12, 24, and 48 h after disbudding, and kids were weighed daily until 2 d post-disbudding. Vocalizations, tail flicks, and struggle behavior during disbudding were recorded. Cameras were mounted over home pens; continuous and scan observations over 12 periods of 10 min each, in the 48 h after disbudding, captured frequency of locomotion and pain-specific behaviors. Repeated measures and linear mixed models assessed treatment effects on outcome measures during and after disbudding. Models accounted for sex, breed, and age as random effects, and Bonferroni adjustments accounted for multiple comparisons. At 15 min after disbudding, XML kids had lower plasma cortisol concentrations compared with L (50.0 ± 13.2 vs. 132.8 ± 13.6 mmol/L) and M kids (50.0 ± 13.2 vs. 145.4 ± 15.7 mmol/L). Cortisol was also lower in XML kids over the first hour after disbudding compared with L kids (43.4 ± 9 vs. 80.2 ± 9 mmol/L). Change from baseline PGE was not affected by treatment. Behaviors observed during disbudding did not differ by treatment group. Treatment affected MNT such that M kids were more sensitive overall compared with sham kids (0.93 ± 0.11 kgf vs. 1.35 ± 0.12 kgf). None of the recorded post-disbudding behaviors were affected by treatment, but study activities did influence behavior over time, with kid activity levels declining in the first day after disbudding but largely recovering thereafter. We conclude that none of the drug combinations investigated here appeared to fully attenuate pain indicators during or after disbudding, but triple modality seems to have offered partial relief compared with some of the single-modality treatments.
在美国，奶山羊羔羊通常在不进行疼痛缓解的情况下进行去角。我们的目标是通过监测去角羔羊血浆生物标志物和行为的变化来确定一种有效的疼痛管理策略。总共42只羔羊（去角时5 - 18日龄）被随机分配到7种处理中的1种（每种处理n = 6只）：假处理；0.05 mg/kg肌肉注射赛拉嗪（X）；4 mg/kg皮下注射缓冲利多卡因（L）；1 mg/kg口服美洛昔康（M）；赛拉嗪和利多卡因（XL）；赛拉嗪和美洛昔康（XM）；赛拉嗪、美洛昔康和利多卡因联合使用（XML）。在去角前20分钟进行处理。一名经过培训且对处理不知情的人员对所有羔羊进行去角；假处理的羔羊处理方式类似，只是烙铁是冷的。在去角前（-20、-10和 -1分钟）和去角后（1、15和30分钟，以及1、2、4、6、12、24、36、48小时）采集颈静脉血样（3 mL），并分析皮质醇和前列腺素E（PGE）。在去角后4、12、24和48小时进行机械伤害性感受阈值（MNT）测试，并且每天对羔羊称重直至去角后2天。记录去角过程中的鸣叫、甩尾和挣扎行为。在羔羊圈舍上方安装摄像头；在去角后的48小时内，分12个时间段，每个时间段持续10分钟进行连续和扫描观察，记录运动频率和疼痛特异性行为。重复测量和线性混合模型评估去角期间和之后处理对结果指标的影响。模型将性别、品种和年龄作为随机效应，Bonferroni校正用于多重比较。去角后15分钟，XML组羔羊的血浆皮质醇浓度低于L组（50.0 ± 13.2 vs. 132.8 ± 13.6 mmol/L）和M组（50.0 ± 13.2 vs. 145.4 ± 15.7 mmol/L）。与L组羔羊相比，去角后第一小时内XML组羔羊的皮质醇也较低（43.4 ± 9 vs. 80.2 ± 9 mmol/L）。处理对PGE相对于基线的变化没有影响。去角过程中观察到的行为在各处理组之间没有差异。处理对MNT有影响，使得M组羔羊总体上比假处理组羔羊更敏感（0.93 ± 0.11 kgf vs. 1.35 ± 0.12 kgf）。记录的去角后行为均未受到处理的影响，但研究活动确实随时间影响行为，羔羊的活动水平在去角后的第一天下降，但此后基本恢复。我们得出结论，此处研究的任何药物组合似乎都未在去角期间或之后完全减轻疼痛指标，但与一些单模态处理相比，三模态似乎提供了部分缓解。
