Research shows that high-producing cows are in estrus for a shorter time than low-producing cows.

“If a cow is producing about 70 pounds per day, a four-time-per-day heat-detection program will detect about 90 percent of cows that are in estrus,” says Milo Wiltbank, reproductive physiologist at the University of Wisconsin. “However, this same program will only detect about 50 percent of cows in heat if they are producing above 100 pounds per day.”

The chart below shows how those results worsen when heat detection is done only once or twice per day.