The objective of this study was to evaluate estrous detection using a physical activity and rumination monitoring system in a seasonal calving organic grazing (GRAZ) and a low-input conventional (ZEROGRAZ) dairy herd. The study was conducted from June 2014 to August 2017. During each breeding season, physical activity and rumination were monitored electronically using an activity and rumination monitoring system (HR-LD tags; SCR Engineers Ltd., Netanya, Israel). Signals resulting from the activity and rumination monitoring system for individual cows were used to determine consistency of the values using this system with the breeding date of cows. Breeding dates were determined using Estrotect^TM patches. The study included 1,463 breeding dates from 531 cows. Within the GRAZ herd, during the summer breeding season the monitoring system was less sensitive for estrous detection (33.8 %) than during the winter breeding season (79.8 %).The activity and rumination monitoring system had a sensitivity of 56.7 %, specificity of 99.3 % and positive predictive value of 59.8 % for the GRAZ herd, and sensitivity of 70.1 %, specificity of 99.2 % and positive predictive value of 66.3 % for the ZEROGRAZ herd. For cows that were determined to be pregnant and subsequently calved as a result of the mating, the sensitivity for estrous detection was slightly greater for the GRAZ (60.7 %) and ZEROGRAZ (72.5 %) herds. The activity and rumination monitoring system evaluated in this study has potential for estrous detection in grazing herds during the winter breeding season and in small-input dairy herds during both, winter and summer breeding seasons.

本研究的目的是在季节性产犊有机放牧 (GRAZ) 和低投入常规 (ZEROGRAZ) 奶牛群中使用身体活动和反刍监测系统评估发情检测。该研究于 2014 年 6 月至 2017 年 8 月进行。在每个繁殖季节，使用活动和反刍监测系统（HR-LD 标签；SCR Engineers Ltd., Netanya, Israel）以电子方式监测身体活动和反刍。从单个奶牛的活动和反刍监测系统产生的信号用于确定使用该系统的值与奶牛繁殖日期的一致性。育种日期使用 Estrotect ^TM确定补丁。该研究包括来自 531 头奶牛的 1,463 个繁殖日期。在 GRAZ 牛群中，夏季繁殖季节监测系统对发情检测的敏感度（33.8 %）低于冬季繁殖季节（79.8 %）。活动和反刍监测系统的灵敏度为 56.7 %，特异性为 99.3 % 和 59.8 % 的阳性预测值对于 GRAZ 畜群，敏感性为 70.1 %，特异性为 99.2 %，阳性预测值为 66.3 % 的 ZEROGRAZ 畜群。对于确定怀孕并随后因交配而产犊的奶牛，GRAZ (60.7 %) 和 ZEROGRAZ (72.5 %) 牛群的发情检测灵敏度略高。