FIG. 1.

Experimental design and results for classification of fertility in beef heifers using serial embryo transfer (ET). See text for detailed description of results. Each row of numbers will not add up to 269 because of occasional death loss or removal of heifers from the study for health reasons. Further, 37 heifers did not have a CL at least once, and five heifers did not have a CL on two occasions. CIDR, controlled intravaginal drug releasing device; GnRH, gonadotropin releasing hormone; PGF2α, prostaglandin F2 alpha.