Artificial insemination (AI) promotes genetic and
economic gains through the use of genetically superior
bulls. Implementation of AI programs based on estrus
detection in suckled beef herds is hampered by postpartum
anestrus, estrus detection (ED) failure, large farms, many
animals per lot, and labor costs [6]. Timed AI (TAI)
programs allow insemination of cows regardless of cyclic
status and might eliminate the need for ED. These
programs also provide a systematic approach to the use of
AI, facilitating its use in beef herds [6,7]. Timed AI programs
allow insemination of all cows at the beginning of the BS;
therefore, it is reasonable to hypothesize that it increases
the proportion of pregnant cows early in the BS and
consequently the overall proportion of cows pregnant the
end of the BS. Although there are limited data for beef cows,
there are numerous reports in dairy cows that support our
hypothesis