Miller W M, Harkness J W, Richards M S, Pritchard D G
Res Vet Sci. 1980 May;28(3):267-74.
Records of treatments for respiratory disease among 952 calves in a large intensive veal unit were analysed. The frequency of disease was heavily age-dependent in the 34 batches of 28 calves with a peak at five weeks of age and little disease before the fourth or after the eighth week. The effect was evident for all of the three indices of disease examined: the numbers of first treatments, numbers of new courses of treatment and the total number of treatments. Transient synchronisation of outbreaks of disease in separate batches was observed but attempts to correlate the level of disease with climatic events, using data from local meteorological stations, were unsuccessful. Disease was shown to be clustered within crops of calves at one end of the housing or the other, indicating that contact spread may have been important. A variation in the amount of disease on each day of the week may have been attributable to restricted feeding on Sundays.
对一个大型集约化小牛肉生产单元中952头犊牛的呼吸道疾病治疗记录进行了分析。在34组每组28头犊牛中，疾病发生频率与年龄密切相关，在5周龄时达到高峰，在第4周之前和第8周之后疾病较少。在所检查的所有三个疾病指标中都明显体现了这种影响：首次治疗次数、新疗程治疗次数和总治疗次数。观察到不同批次疾病爆发存在短暂同步性，但利用当地气象站的数据将疾病水平与气候事件进行关联的尝试未成功。结果表明疾病集中在牛舍一端或另一端的犊牛群中，这表明接触传播可能很重要。一周中每天疾病数量的变化可能归因于周日的限饲。
