Efficacy of a continuous measurement by pedometer for estrus detection in dairy cows

The objective of this study was to determine the efficacy of a continuous measurement system such as the pedometer for estrus detection in dairy cows. Forty five Holstein cows were in freestall housing that contained an automatic milking system. Pedometers were attached with bands to the cow's front right legs and data were continuously transmitted to a computer. At the time of estrus, the number of steps taken was measured by a pedometer, and this was compared with the average number of steps taken at the time of anestrus. Cows were regarded as being estrus when the number of steps taken at the time of estrus was 1.6 times or more than that at the time of anestrus. Further, the cows were observed for estrus every day by examination of the ovary and uterus by rectal palpation or ultrasonography. Some cows were inseminated artificially. All cows ovulated, and 31 (68.9%) cows were detected by the pedometer as being in the estrus stage (detected cows); however 14 (31.1%) were not in this state (undetected cows). No differences were observed in the number of steps taken at the time of anestrus between the estrus detected and undetected cows as determined by the pedometer. There were significant differences in the number of steps taken and increasing rate of steps at the time of estrus between the estrus detected and undetected cows as detected by the pedometer. The duration of estrus in the detected cows was 12.1 +- 5.2 h although it differed greatly among individual cows (4 to 14 h). The cows were monitored during the onset of estrus and were distributed into groups based on 4-h periods. There were no differences in the onset of estrus in the hourly periods. There were significant differences in the conception rate of detected (10/22, 45.5%) and undetected cows (1/14, 7.1%). These results demonstrate that a continuous measurement system such as the pedometer can be effectively used to detect estrus in dairy cows. However, cows with poor estrus activity could not be detected even when the pedometer is used. Therefore, further experiments are required to increase the detection accuracy for cows with poor estrus activity.