Abstract

Pain alleviation associated with surgical castration of piglets is a debated welfare issue. The present study compares the effect of different protocols involving analgesia and/or anaesthesia or sedation suitable under field conditions, with the aim to alleviate pain due to castration in piglets. A randomised within-litter design, with 50 replicates, compared 7 treatments applied 10 min before castration: HAND: positive control, handling only; CTRL: negative control, physiological saline, i.m.; MEL: meloxicam, i.m.; AZA: azaperone, i.m.; PROC: local anaesthesia with procaine and adrenaline, subcutaneously; AZA-MEL: joint administration of azaperone and meloxicam; PROC-MEL: procaine and meloxicam. Efficacy of pain relief was assessed during a 180 min period after castration by serum cortisol and glycaemia, algometry and behaviour. CTRL, AZA, PROC and AZA-MEL piglets showed an increase in cortisol concentration 60 min after castration compared to HAND. Both groups with azaperone (AZA and AZA-MEL) developed concentrations even higher than CTRL (p < .001). HAND treatment showed cortisol levels comparable only to MEL and PROC-MEL (p > .05). CRTL and PROC piglets reacted to the algometer at an average lower pressure than HAND (p = .03), differently to the other treatments that showed similar skin sensitivity to HAND (p > .05). No differences in glycaemia and behaviour were observed among treatments. The results suggest that using meloxicam alone might offer a promising option in reducing the expression of pain-related parameters in piglets after surgical castration, however, it appears more efficient when used alone than in association with the anaesthetic agents tested. Procaine administered alone and azaperone seems unsuited to the purpose considered.

• HIGHLIGHTS

• Meloxicam used alone is suggested for reducing the expression of pain-related parameters in piglets after surgical castration;

• When a protocol using procaine is used on the farm during piglets castration, the association with meloxicam reduces some pain-related indicators;

• Procaine administered alone and azaperone seems unsuited to manage pain after surgical castration of piglets.

摘要

与仔猪手术去势相关的疼痛缓解是一个有争议的福利问题。本研究比较了在田间条件下适用于镇痛和/或麻醉或镇静的不同方案的效果，目的是减轻仔猪去势引起的疼痛。随机窝仔设计，重复50次，比较cast割前10分钟应用的7种治疗方法：HAND：阳性对照，仅处理；CTRL：阴性对照，生理盐水，即时；梅尔：美洛昔康，即时消息；氮杂：azaperone，即时通讯；PROC：皮下注射普鲁卡因和肾上腺素进行局部麻醉；氮杂-MEL：氮杂哌酮和美洛昔康的联合给药；PROC-MEL：普鲁卡因和美洛昔康。cast割后180分钟内，通过血清皮质醇和血糖，血脂测定法和行为来评估止痛效果。CTRL，AZA，与HAND相比，去势后60分钟，PROC和AZA-MEL仔猪的皮质醇浓度增加。两组均含氮杂哌酮（AZA和AZA-MEL）的浓度甚至高于CTRL（p  <.001）。HAND处理显示皮质醇水平仅与MEL和PROC-MEL相当（p  > .05）。CRTL和PROC仔猪对血压计的反应压力平均低于HAND（p  = .03），这与其他皮肤对HAND的敏感性相似（p  > .05）不同。治疗之间未观察到血糖和行为的差异。结果表明，单独使用美洛昔康可能为减少手术去势后仔猪疼痛相关参数的表达提供了一个有前途的选择，但是，与与所测试的麻醉剂联合使用时，单独使用美洛昔康似乎更有效。单独服用普鲁卡因和氮杂哌酮似乎不适合所考虑的目的。

• 强调

• 建议单独使用美洛昔康以减少手术去势后仔猪疼痛相关参数的表达。

• 在仔猪去势期间在农场使用普鲁卡因的方案时，与美洛昔康联用可减少一些与疼痛有关的指标；

• 单独施用普鲁卡因和氮杂哌酮似乎不适合管理小猪去势后的疼痛。