Duration of estrus and the number of mounts received during estrus were recorded by HeatWatch. If any part of estrus for a cow occurred at the same time as estrus for another cow, the cow was considered to have concurrent estrus with the other cow. Cows in the drylot had a shorter (P < 0.02; 61.8 ± 3.1 h) interval to estrus after PGF2α compared with cows on pasture
(72.8 ± 3.3 h). The interval to estrus was longer (P