The number of mounts received per estrus and the duration of estrus are both affected by the number of days after calving. Only 19% of first postpartum ovulations in dairy cows were detected by visual observation, and this increased to 37 and 79% at the second and third postpartum ovulations, respectively (Peter and Bosu, 1986). Postpartum beef cows received less than 20 mounts during the first postpartum estrus, which was less than 6 h in duration (Ciccioli et al., 2003; Lents et al., 2008). Increasing the number of cows in estrus could allow more cows to be detected in estrus when they are estrus for a short duration with few mounts. Our results indicate that detecting a single beef cow in estrus can be very difficult in drylot and in pasture situations. Increased visual observation may be needed to detect estrus when only 1 cow is in estrus. Synchronization of estrus increased the number of cows in estrus at the same time, increased the number of times cows in estrus were mounted and the duration of estrus, and decreased the longest interval between mounts received. This greater display of estrous behavior could allow fewer visual observations to detect cows in estrus and enhance the efficiency of AI.