[目的] 对于高产奶牛来说,酸中毒是关乎健康和福利的重要问题,在确诊酸中毒前几天,其反刍行为就会受到影响。因此,奶牛的行为模式有望成为发现其早期酸中毒的关键指标。然而,目前行为模式分析在 预测酸中毒方面的发展还有很大空间。健康奶牛在酸中毒发作前数周或数月的行为模式可作为该病的危险因素来考量。确定酸中毒奶牛相较于健康奶牛是否表现出与该病相关的特定早期行为模式。[方法] 研究在两个西班牙商业农场和两个意大利商业农场展开,通过使用加速度计项圈,对奶牛从产犊到酸中毒前15 天的每日站立、躺卧、行走、反刍、进食时间进行详细记录。酸中毒组（n=10）为泌乳期间经两国兽医的诊断发生酸中毒的奶牛,酸中毒是由两国兽医记录诊断的。在西班牙农场,酸中毒病例还通过瘤胃pH探测胶囊来进一步确认（当一头奶牛瘤胃pH值低于5.6且持续至少50 min/d时被确认患有酸中毒）。之后,建立对照组,选取胎次和泌乳期与酸中毒组奶牛相同的健康奶牛（n=10）,两组奶牛在酸中毒诊断前的日产奶量相近。采用方差分析法,对每头奶牛的所有行为数据进行群体效应的评估,分析它们在酸中毒与健康状态下所有行为（站立、躺卧、行走、反刍、进食时间）的截距和回归曲线斜率差异。[结果] 两组奶牛在反刍、躺卧和进食持续时间的截距和回归曲线斜率有显著差异。酸中毒组奶牛相比对照组在发作前85 天躺卧时间（10.55 h/d vs 10.22 h/d）、进食时间（3.55 h/d vs 3.41 h/d）更长（P<0.001）。与对照组相比,酸中毒奶牛在发作前115 天的反刍时长较长（7.73 h/d vs 6.86 h/d）,但在发作前35 天较短（7.33 h/d vs 7.81 h/d）。此外,酸中毒前反刍时长随时间变化的趋势也不同,酸中毒组奶牛的回归曲线斜率系数更低（P<0.001）。[结论] 患酸中毒的奶牛可能在发作前数月就表现出不同的行为模式（如反刍时间较长）。但还需更大样本量开展进一步研究,以此确认行为模式的差异是否可被视为诊断酸中毒的依据。

[Objective] Acidosis is a major health and welfare issue,especially in high-producing dairy cows. During acidosis,rumination is affected,as early as a few days before diagnosis. For this reason,behavioural patterns can be considered as promising indicators for the early detection of acidosis. However,the power of behaviour analysis to predict acidosis can go much further,and behavioural patterns of healthy dairy cows,weeks or months before the onset of acidosis,could be used as a risk factor for the disease. The aim of this study was to determine whether cows that will subsequently develop acidosis,show early distinctive behavioural patterns associated with the disease compared to healthy cows. [Method] Daily hours spent standing,lying down, walking,ruminating and eating were recorded from calving to 15 d prior acidosis using accelerometer collars on two commercial farms in Spain and two others in Italy. The acidosis group （n=10）included cows that suffered an episode of acidosis during lactation. Acidosis was diagnosed by veterinary records in both countries. In Spanish farms,acidosis cases were confirmed by rumen pH measured by boluses（smaXtec Animal Care GmBH,Graz, Austria;a cow was confirmed as suffering from acidosis when exhibiting a rumen pH below 5.6 for at least 50 min/ d）. A control group of healthy cows（n=10）balanced for parity and lactation stage was constituted afterwards. The daily milk production before the diagnosis of acidosis was similar in both groups. The group effect（acidosis vs healthy）on the intercept and the slope of the regression curve of each individual cow for all behaviours was analyzed using ANOVA. [Result] The group significantly affected the intercept of the regression curve for the ruminating ,lying down and eating duration showing that cows in the acidosis group spent more time lying（10.55 h/d vs 10.22 h/d）and eating（3.55 h/d vs 3.41 h/d）85 days before the onset of acidosis（P<0.001）,compared to control cows. In addition,the rumination duration of acidosis cows was higher（7.73 h/d vs 6.86 h/d）115 d before the onset of acidosis , but lower（7.33 h/d vs 7.81 h/d）35 d before the onset of acidosis ,compared to the control cows. The trend in rumination duration over time prior to acidosis was also different as shown by the lower slope coefficient for acidosis cows（P<0.001）. [Conclusion] This study suggested that cows that will subsequently suffer from acidosis might expressed distinct behavioural patterns（e.g. rumination）already months prior to the onset of acidosis. Further research with a larger sample size is needed to confirm whether differences in behavioural patterns can be considered as promoters of acidosis.