Epidemiology Unit, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan.
BMC Vet Res. 2021 Sep 9;17(1):305. doi: 10.1186/s12917-021-03008-3.
Animal movement is considered the most significant factor in the transmission of infectious diseases in livestock. A better understanding of its effects would help provide a more reliable estimation of the disease spread and help develop effective control measures. If the movement pattern is heterogeneous, its characteristics should be considered in epidemiological analyses, such as when using simulation models to obtain reliable outputs. In Japan, following the bovine spongiform encephalopathy epidemic, a traceability system for cattle was established in 2003, and the registration of all cattle movements in the national database began. This study is the first to analyze cattle movements in Japan. We examined regional and seasonal heterogeneity in dairy cow movements, which accounted for most Japanese breeding cattle.
In the 14 years from April 2005 to March 2018, 4,577,709 between-farm movements of dairy cows were recorded, and the number of movements was counted by month and age for both inter- and intra-regional movements. As a result, two characteristic round-trip movements were observed: one was non-seasonal and inter-regional movements related to cattle-breeding ranches in Hokkaido (the northern region of Japan), which consists of the movement of cows around ages 6 to 8 and 21 to 23 months old. In addition, the seasonal movement of heifers for summer grazing within Hokkaido occurred in May and October at the peak ages of 13 to 14 and 19 to 20 months old, respectively. The observed heterogeneity seemed to reflect the suitability of raising the Holstein breed in Hokkaido and the shortage of supply of replacement heifers and available farming areas outside Hokkaido.
Understanding the patterns of dairy cow movements will help develop reliable infectious disease models and be beneficial for developing effective control measures against these diseases.
动物的移动被认为是家畜传染病传播的最重要因素。更好地了解其影响将有助于更可靠地估计疾病的传播，并有助于制定有效的控制措施。如果移动模式是异质的，那么在流行病学分析中应考虑其特征，例如在使用模拟模型获得可靠结果时。在日本，继牛海绵状脑病流行之后，2003 年建立了牛的可追溯系统，并开始在国家数据库中登记所有牛的移动。本研究首次分析了日本的牛移动情况。我们检查了奶牛移动的区域和季节性异质性，这占了大多数日本繁殖牛。
在 2005 年 4 月至 2018 年 3 月的 14 年中，记录了 4577709 次奶牛场之间的农场间移动，并且按月和年龄对跨区域和区域内的移动次数进行了计数。结果观察到了两个特征性的往返移动：一个是非季节性的，与北海道（日本北部）的奶牛养殖场有关的跨区域移动，其中包括 6 至 8 月龄和 21 至 23 月龄的奶牛移动。此外，北海道内的夏季放牧小母牛的季节性移动发生在 5 月和 10 月，高峰期分别为 13 至 14 月龄和 19 至 20 月龄。观察到的异质性似乎反映了在北海道饲养荷斯坦奶牛的适宜性，以及北海道以外的后备小母牛供应短缺和可用农田短缺。
了解奶牛移动的模式将有助于开发可靠的传染病模型，并有助于制定针对这些疾病的有效控制措施。
