title: Effect of estrus synchronization treatment after luteolysis on Holstein heifers as embryo transfer recipients.
abstract: This study was designed to evaluate the effect of estrus synchronization treatments on recipient heifers for embryo transfer (ET). Holstein heifers were separated into the following three groups: (i) an administration of 50 µg GnRH (gonadotropin-releasing hormone) analog was given to heifers at a random stage of the estrus cycle, followed 7 days later by two administrations of 7.5 mg prostaglandin F2 alfa analog (PG) as control; (ii) another administration of 100 µg GnRH was given to the control group at 48 h after the administration of PG as the second GnRH group; and (iii) an administration of 0.75 mg estradiol benzoate (E2) was given to the control group at 24 h after the administration of PG as the E2 group. Each method caused estrus synchronization. Fresh embryos were nonsurgically transferred into the suitable recipients that had a functional corpora lutea (CL) 7 days after estrus. The E2 group showed a significantly higher (P < 0.01) rate of estrus synchronization (98.9%) at 1-3 days after PG administration and the final pregnancy rate of the E2 group (50.6%) was also significantly higher than the other groups (37.1%, P < 0.05 and 30.9%, P < 0.01, respectively). These findings demonstrate that E2 administration 24 h after PG protocol is effective for estrus synchronization of Holstein heifers, thus improving the productivity of ET.
authors: Department of Animal Science, Nippon Veterinary and Life Science University, Musashino, Japan.
authors: Tatsuyuki
authors: T
authors: Yoshida
authors: Taro
authors: T
authors: Sato
authors: Koji
authors: K
authors: Chiba
authors: Itaru
authors: I
authors: Yoshimura
authors: Masahiro
authors: M
authors: Osada
authors: Konosuke
authors: K
authors: Okada
authors: Hiroki
authors: H
authors: Furuta
authors: Akihiko
authors: A
authors: Ohta
authors: Hitoshi
authors: H
authors: Ushijima
mesh_terms: D000818:Animals; D002417:Cattle; D003338:Corpus Luteum / Q000502:physiology; D004624:Embryo Transfer; D004958:Estradiol / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D004971:Estrus / Q000502:physiology; D004973:Estrus Synchronization / Q000187:drug effects; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000494:pharmacology; D003341:Luteolysis; D011247:Pregnancy; D013997:Time Factors
chemical_list: C074283:estradiol 3-benzoate; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol