McCracken Leanne, Waran Natalie, Mitchinson Sheryl, Johnson Craig B
Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand.
Vet Anaesth Analg. 2010 Jul;37(4):375-81. doi: 10.1111/j.1467-2995.2010.00547.x.
To investigate the effects of age at castration on the subsequent behavioural response to tail docking.
Randomised prospective blinded experimental study.
Forty-five male lambs were admitted to the study at birth.
The lambs were allocated into two groups for castration by rubber ring at 1 (1D, n = 20) or 10 (10D, n = 25) days of age. Following castration both groups of lambs were tail-docked by rubber ring at between 26 and 34 days of age. Their behavioural responses to tail docking were recorded by video for 30 minutes before (n = 11) and 30 minutes after (n = 45) tail docking. Statistical differences were tested using anova with Mann-Whitney post-hoc testing.
Two data sets were removed resulting in n = 19 and = 24 at 1D and 10D, respectively. A significant increase in the incidence of active and abnormal postural behaviour was seen in both groups after tail docking. Three behaviours were significantly different (p < 0.05) between the two groups. These behaviours were rolling, standing unsteadily and the total proportion of time standing with abnormal posture. These behaviours all had greater incidence in the lambs castrated at 1D of age.
Lambs castrated at 1D appeared to perceive a greater intensity of pain after subsequent tail docking than lambs castrated at 10D.
The timing of a single noxious stimulus in young animals can affect subsequent pain perception.
研究去势年龄对随后断尾行为反应的影响。
随机前瞻性盲法实验研究。
45只雄性羔羊出生时纳入本研究。
羔羊按年龄分为两组，分别在1日龄（1D组，n = 20）或10日龄（10D组，n = 25）时用橡胶环去势。去势后，两组羔羊均在26至34日龄时用橡胶环断尾。在断尾前30分钟（n = 11）和断尾后30分钟（n = 45）通过视频记录它们对断尾的行为反应。使用方差分析和曼-惠特尼事后检验来检验统计学差异。
去除两个数据集后，1D组和10D组分别剩余n = 19和n = 24。两组断尾后主动和异常姿势行为的发生率均显著增加。两组之间有三种行为存在显著差异（p < 0.05）。这些行为是翻滚、站立不稳以及异常姿势站立的总时间比例。这些行为在1日龄去势的羔羊中发生率更高。
1日龄去势的羔羊在随后断尾后似乎比10日龄去势的羔羊感觉到更强的疼痛强度。
幼年动物单次有害刺激的时机可影响随后的疼痛感知。
