A research study undertaken at Kansas State University and published this week in the Journal of Dairy Science specifically stated that scanning by ultrasonography confirmed that 88.6% of cows identified by activity (by the MooMonitor) were in estrus. This compared favorably with other systems tested which were 70% to 80% accurate.
What the research showed was that the majority of heats do happen during the night and that there was a real difference in the gap between the onset of heat and conception time depending on the age of the animal and the number of previous pregnancies.
In addition to detecting cows in heat, optimizing the timing of insemination can significantly improve conception rates with less effort and greater efficiency meaning cows are more productive.