Percentages of controlled internal drug release (CIDR) devices retained, presentation of estrus and gestations summarized for the different groups.

Group A (Control) = crossbred heifers inseminated with cryopreserved, frozen-thawed sperm without added recombinant heparin binding proteins (rHBPs), i.e., control group. Group B (rHBPs) = crossbred heifers inseminated with cryopreserved, frozen-thawed sperm with added rHBPs, i.e., treatment group.