title: Comparison between different protocols of synchronization and their efficiency on pregnancy rate of dairy cattle.
abstract: In order to determine different protocols of synchronization and their efficiency on pregnancy rate after fixed-timed AI (TAI), 120 dairy Holstein cows (n=120) were assigned randomly to six groups: (1) two injections of Prostaglandin F(2alpha) (PG(f2alpha)) with 12 days apart as a control group, (2) two injections of Gonadotropin Releasing hormone (GnRH) with 9 days apart and an injection of PG(f2alpha) at day 7, (3) injection of GnRH and PG(f2alpha) with 7 days apart, then single injection of Estradiol Benzoate (EB) after 48 h, 4) injection of progesterone (P4) in conjugation with EB then after 7 days PG(f2alpha) injection and after 48 h an injection of GnRH were done, 5) as group 4 but EB was used instead of GnRH, 6)injections of PG(f2alpha) and EB conjugated with Human Chronic Gonadotrophin (hCG) with 12 h apart. Animals in group 1 (control), groups 2-5 and group 6 were inseminated after 72, 20 and 36 h, respectively. Serum P4 concentration of group 4 (4.43 +/- 1.50 ng mL(-1)) was higher than control group (2.34 +/- 1.36 ng mL(-1)) at day 5 after insemination (p < 0.05); P4 concentrations of groups 3 and 4 have significant differences with control group (2.69 +/- 2.64 and 2.56 +/- 1.40 versus 0.81 +/- 0.41 ng mL(-1), respectively, p < 0.05) at a day after second injection and groups 4 and 5 were in higher level of P4 concentration than control group at insemination time (3.14 +/- 1.9 and 2.89 +/- 1.8 versus 0.45 +/- 0.19 ng mL(-1) respectively, p < 0.05). Pregnancy rate were 0, 50, 45, 10, 30 and 45% for group 1 (control) through 6, respectively.
authors.affiliation: Department of Animal Science, University of Razi, Iran.
authors.forename: A
authors.initials: A
authors.lastname: Karimi
authors.forename: H
authors.initials: H
authors.lastname: Karami
authors.forename: M M
authors.initials: MM
authors.lastname: Moini
authors.forename: A A
authors.initials: AA
authors.lastname: Ahmadi Sefat
authors.forename: E
authors.initials: E
authors.lastname: Haghvirdilu
mesh_terms: D000818:Animals; D002417:Cattle; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D003008:Cloprostenol / Q000494:pharmacology; D003270:Contraceptive Agents / Q000494:pharmacology; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D030762:Estrous Cycle / Q000187:drug effects* / Q000502:physiology; D004973:Estrus Synchronization / Q000379:methods*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D007315:Insemination, Artificial; D008186:Luteolytic Agents / Q000494:pharmacology; D011247:Pregnancy; D018873:Pregnancy Rate; D011270:Pregnancy, Animal; D011374:Progesterone / Q000097:blood / Q000494:pharmacology; D011897:Random Allocation; D012102:Reproductive Control Agents / Q000494:pharmacology
chemical_list: D006063:Chorionic Gonadotropin; D003270:Contraceptive Agents; D008186:Luteolytic Agents; D012102:Reproductive Control Agents; C074283:estradiol 3-benzoate; D007987:Gonadotropin-Releasing Hormone; D003008:Cloprostenol; D011374:Progesterone; D004958:Estradiol