title: Embryo production by ovum pick up in unstimulated calves before and after puberty.
abstract: The possibility of producing embryos from oocytes repeatedly collected from unstimulated calves was tested, and results obtained before and after puberty were compared in the same animals. Ovum pick-up (OPU) coupled with in vitro embryo production was used on 2 sets of 7 and 9 calves, aged 7 to 10 m.o. at the start of the experiment. The oocytes were collected twice a week during a 2-m.o. period before puberty and a 1-m.o. period after puberty. Oocytes were fertilized and co-cultured with cumulus cells in modified synthetic oviduct fluid (SOF) up to Day 7 post insemination. Some Day 7 blastocysts were vitrified and transferred to recipient heifers. An average of 3.8 to 6.8 follicles was punctured per OPU session; 1.9 to 3.1 oocytes were collected, of which more than 60% were of good quality. The number of punctured follicles and collected oocytes varied between donors. Blastocyst rates of 19 to 27% were obtained for the 2 sets. Three normal calves were born from the transfer of 20 vitrified embryos. While no significant difference was observed for the first set of calves, a significant decrease in the number of punctured follicles was observed after puberty in the second set. A direct correlation was also obtained between the number of follicles punctured before and after puberty in the same animal. In conclusion, oocytes can be collected by repeated OPU in calves 7 to 10 m.o. old without affecting their growth or the onset of puberty. An average of 5 to 11 (range 0 to 16) blastocysts per donor was produced over 2 month. However, important variations were found between donors. The correlation observed for the number of follicles punctured before and after puberty suggests that this parameter is determined before puberty.
authors.affiliation: Université catholique de Louvain, Unité des Sciences vétérinaires, Louvain-la-Neuve, Belgium.
authors.forename: V
authors.initials: V
authors.lastname: Majerus
authors.forename: R
authors.initials: R
authors.lastname: De Roover
authors.forename: D
authors.initials: D
authors.lastname: Etienne
authors.forename: S
authors.initials: S
authors.lastname: Kaidi
authors.forename: A
authors.initials: A
authors.lastname: Massip
authors.forename: F
authors.initials: F
authors.lastname: Dessy
authors.forename: I
authors.initials: I
authors.lastname: Donnay
mesh_terms: D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000502:physiology*; D002417:Cattle; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary*; D018587:Oocyte Donation / Q000379:methods / Q000662:veterinary*; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000662:veterinary*; D012741:Sexual Maturation; D015053:Zygote / Q000166:cytology / Q000502:physiology