Free-ranging cows at Biebrza Marshes

A herd of thirty semi-free grazing dairy cows was studied with GPS telemetry in 2016. The cows were followed across whole grazing season: from 27th April till last day of October. GPS logger (Holux RCV-3000) with a waterproof coating was attached to a collar on one of the cow’s necks. The logger was taken off, charged and mounted once, on average, at 1.6 days intervals and acquired data at 1-minute intervals. GPS data were collected on 119 out of 187 days of grazing season. The whole herd moved together, therefore it was only necessary to follow one animal. During that time adult cows where not supplementary fed. They were also not milked by the farmer but instead nursed their calfs. The cows were released around 5:50 am from a private farm, where they headed out on their own to foraging sites in the wetland of Biebrza National Park. They were later led back to the farm by a farmer about 4:30 pm. Local2016年，本研究采用GPS遥测技术，对30头半自由放牧奶牛群体开展了观测研究。观测覆盖完整放牧季，时间为4月27日至10月最后一日。研究人员将带有防水涂层的GPS记录器（Holux RCV-3000）安装于其中一头奶牛的颈部项圈处。该记录器平均每1.6天取下一次进行充电并重新安装，以1分钟的采样间隔采集数据。整个放牧季共计187天，最终获取其中119天的GPS观测数据。由于整群奶牛同步移动，仅需追踪单头个体即可代表全群活动情况。实验期间，成年奶牛未获得补充饲喂，农场工作人员亦未对其挤奶，奶牛自行哺育犊牛。每日清晨约5:50，奶牛从私人农场被放出，随后自行前往别布扎国家公园（Biebrza National Park）的湿地觅食区域。当日约下午4:30，由农场工作人员将牛群赶回农场。