A single frozen-thawed Wagyucattle embryo was transferred trans-cervically with astandard 0.25 mL embryo transfer instrument into the uter-ine horn ipsilateral to the CL. All embryos were assigneda developmental stage and quality grade according tostandards of the International Embryo Transfer Society(Robertson and Nelson, 1998). Developmental stage codeswere: 3 = early morula; 4 = morula; 5 = early blastocyst;and, 6 = blastocyst. Quality codes were: 1 = symmetricaland spherical embryo mass with individual blastomeresthat were uniform in size, color, and density with at least85% of the cellular material intact (excellent or good); and,2 = moderate irregularities in overall shape of embryonicmass or in size, color and density of individual cells withat least 50% of the cellular material intact (fair). Embryosreceiving stage codes of less than 3 or greater than 6 or poorquality embryos (quality score of 3 or 4) were excludedfrom the study. Pregnancy diagnosis was performed 40 dafter embryo transfer by ultrasonography