Ekstrand C, Carpenter T E
Department of Animal Environment and Health, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, Skara, Sweden.
Acta Vet Scand. 1998;39(2):229-36. doi: 10.1186/BF03547795.
This study aimed at analysing the temporal aspects of foot-pad dermatitis in Swedish broilers. The information on disease prevalence and severity was based on a 2-year foot-health surveillance programme where information on producer, breed, feed manufacturer, region, abattoir, date of slaughter and several other variables was recorded. The seasonal effects were evaluated using classical multiplicative decomposition time series analysis. This study shows that there has been a significantly consistent decrease in the prevalence of severe foot-pad lesions during the first 2 years of the programme. Looking at the development over time we found a trend-cycle component of 10.4% and a seasonal component of 48.7% resulting in a total adjusted R-square value of 58.5% for the total foot-pad score. This means that almost 60% of the variation in flock foot-pad score can be explained by the variable 'time', and that this variation was mainly related to seasonal effects but also to a general decreasing trend over the study period. However, substantial differences in temporal patterns among slaughterhouses, feed suppliers and regions were found. The time series analysis approach was found to be useful for this type of investigation when evaluating the effects of an intervention programme, and it can also be applied for projecting the future development of disease status in a stable population.
本研究旨在分析瑞典肉鸡脚垫皮炎的时间特征。疾病流行率和严重程度的信息基于一项为期两年的足部健康监测计划，该计划记录了有关生产商、品种、饲料制造商、地区、屠宰场、屠宰日期以及其他几个变量的信息。使用经典乘法分解时间序列分析评估季节效应。本研究表明，在该计划的前两年中，严重脚垫病变的流行率显著且持续下降。观察随时间的发展，我们发现趋势周期成分占10.4%，季节成分占48.7%，脚垫总评分的调整后R平方总值为58.5%。这意味着鸡群脚垫评分中近60%的变化可以由“时间”变量解释，并且这种变化主要与季节效应有关，但也与研究期间的总体下降趋势有关。然而，发现屠宰场、饲料供应商和地区之间的时间模式存在显著差异。在评估干预计划的效果时，发现时间序列分析方法对于此类调查很有用，并且它还可以用于预测稳定种群中疾病状态的未来发展。
