The comparison of the 5-day CO-Synch þ CIDR to two doses of PGF at CIDR removal with four handlings
versus the 7-day CO-Synch þ CIDR with three handlings in a large-scale beef operation would allow
determination of the program that will yield a better AI pregnancy rate. Based on the necessity of this comparison,
a hypothesis was developed that the 5-day CO-Synch þ CIDR protocol would improve fertility of beef cows
following TAI compared with the 7-day CO-Synch þ CIDR protocol.