title: The effect of internal and external factors on bovine embryo transfer results in a tropical environment.
abstract: The objectives of this work were to determine the effect of external (synchronization methods, month, embryo origin and farm effects) and internal factors (age and size of CL, embryo development and quality score, synchronization methods, age of recipient, quality of transfer and reuse of recipients) on a commercial embryo transfer program in a tropical environment. In the program 1466 Holstein-Friesian purchased embryos were implanted to zebu/European crossbred recipients under field conditions. There were 502 pregnancies detected in this large-scale extension programme. Synchronization methods, month, embryo origin, and farm effects were found to have affected the success rate of embryo transfer. Due to the hot climate and large distances between recipient farms, seasonal effects, reused recipient pregnancy results and the effect of embryo development stage differed from previously reported results. Investigation by ultrasonograph showed that embryo loss occurred before 35 days of pregnancy. Under field conditions, routine fetal sexing resulted in <5% misidentification. In conclusion, under tropical conditions external factors have a major influence on the results of pregnancy from embryo transfer.
authors.affiliation: Hungarian Academy of Sciences, Institute of Experimental Medicine, Szigony Street 43, Budapest 1083, Hungary. benyei@koki.hu
authors.forename: Balázs
authors.initials: B
authors.lastname: Bényei
authors.forename: István
authors.initials: I
authors.lastname: Komlósi
authors.forename: Anna
authors.initials: A
authors.lastname: Pécsi
authors.forename: Geoffry
authors.initials: G
authors.lastname: Pollott
authors.forename: Cruvinel Heraldo
authors.initials: CH
authors.lastname: Marcos
authors.forename: Alexandre
authors.initials: A
authors.lastname: de Oliveira Campos
authors.forename: Maida Paula
authors.initials: MP
authors.lastname: Lemes
mesh_terms: D000034:Abortion, Veterinary / Q000453:epidemiology; D000375:Aging; D000818:Animals; D002417:Cattle / Q000196:embryology*; D003338:Corpus Luteum / Q000033:anatomy & histology; D004624:Embryo Transfer / Q000662:veterinary*; D047108:Embryonic Development; D004973:Estrus Synchronization; D005260:Female; D005865:Gestational Age; D008297:Male; D011247:Pregnancy; D012621:Seasons; D014329:Tropical Climate