{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,29]],"date-time":"2025-10-29T03:13:28Z","timestamp":1761707608647,"version":"build-2065373602"},"reference-count":51,"publisher":"CSIRO Publishing","issue":"2","license":[{"start":{"date-parts":[[2025,5,27]],"date-time":"2025-05-27T00:00:00Z","timestamp":1748304000000},"content-version":"vor","delay-in-days":8036,"URL":"https:\/\/doi.org\/10.1071\/journalslicense"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2003,5,27]]},"abstract":"<jats:p>Repeat-breeder heifers (RBH) have been shown to present reproductive perturbations during spontaneous cyclicity, which affects oestrus and ovulation. Some of these disturbances (e.g. deviating hormone patterns) are also present during and after cycles of twice-weekly ovum pick-up (OPU), performed according to an optimized schedule allowing normal oestrous cyclicity. In the present study, the effects of OPU on oocyte competence in in vitro maturation (IVM) and in vitro fertilization (IVF) have been evaluated, as were the effects on expression of oestrus and fertility in five RBH (=4 artificial inseminations) and five virgin heifers (VH controls). In total, 269 RBH and 174 VH oocytes were scored for quality prior to IVM and IVF. The number of follicles available for puncture was higher in RBH, but the oocyte recovery rate after OPU was lower in RBH compared with VH controls and the recovered RBH oocytes were of lower quality, as judged by their appearance at retrieval. Confocal laser scanning and transmission electron microscopy of immature oocytes did not reveal any differences between RBH and VH control oocytes with respect to nuclear and mitochondrial status. However, after IVM, the cytoplasmic spatial reorganization of mitochondria and cortical granules was less advanced in RBH, which could contribute to the subfertility that defines the syndrome. Cleavage rates after IVF were similar in RBH and VH controls. Subsequent to the OPU period, in vivo fertility after controlled artificial insemination was comparable with field fertility rates in both RBH and VH.<\/jats:p>","DOI":"10.1071\/rd02094","type":"journal-article","created":{"date-parts":[[2003,8,20]],"date-time":"2003-08-20T03:03:59Z","timestamp":1061348639000},"page":"115-123","source":"Crossref","is-referenced-by-count":15,"title":["Oocyte competence in repeat-breeder heifers: effects of an optimized ovum pick-up schedule on expression of oestrus, follicular development and fertility"],"prefix":"10.1071","volume":"15","author":[{"given":"Ren\u00e9e","family":"B\u00e5ge","sequence":"first","affiliation":[{"name":"ACentre for Reproductive Biology in Uppsala (CRU), Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, PO Box 7039, SE-750 07 Uppsala, Sweden."},{"name":"DTo whom correspondence should be addressed. email: renee.bage@og.slu.se"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sudsaijai","family":"Petyim","sequence":"additional","affiliation":[{"name":"ACentre for Reproductive Biology in Uppsala (CRU), Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, PO Box 7039, SE-750 07 Uppsala, Sweden."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Birgitta","family":"Larsson","sequence":"additional","affiliation":[{"name":"ACentre for Reproductive Biology in Uppsala (CRU), Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, PO Box 7039, SE-750 07 Uppsala, Sweden."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Triin","family":"Hallap","sequence":"additional","affiliation":[{"name":"ACentre for Reproductive Biology in Uppsala (CRU), Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, PO Box 7039, SE-750 07 Uppsala, Sweden."},{"name":"BDepartment of Reproductive Biology, Estonian Agricultural University, Tartu, Estonia."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ann-Sofi","family":"Bergqvist","sequence":"additional","affiliation":[{"name":"ACentre for Reproductive Biology in Uppsala (CRU), Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, PO Box 7039, SE-750 07 Uppsala, Sweden."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hans","family":"Gustafsson","sequence":"additional","affiliation":[{"name":"ACentre for Reproductive Biology in Uppsala (CRU), Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, PO Box 7039, SE-750 07 Uppsala, Sweden."},{"name":"CSwedish Dairy Association, H\u00e5llsta, SE-631 84 Eskilstuna, Sweden."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Heriberto","family":"Rodr\u00edguez-Mart\u00ednez","sequence":"additional","affiliation":[{"name":"ACentre for Reproductive Biology in Uppsala (CRU), Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, PO Box 7039, SE-750 07 Uppsala, Sweden."}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"67","reference":[{"key":"2025102817560903200_R1"},{"key":"2025102817560903200_R2"},{"key":"2025102817560903200_R3"},{"key":"2025102817560903200_R4"},{"key":"2025102817560903200_R5"},{"key":"2025102817560903200_R6"},{"key":"2025102817560903200_R7","unstructured":"Ayalon         N.                           1984      10\u201314 June      The repeat breeding problem.      Proceedings of the Xth International Congress of Animal Reproduction and Artificial Insemination                         41      50      University of Illinois Urbana-Campaign      IL, USA.      (Abstract.)"},{"key":"2025102817560903200_R8"},{"key":"2025102817560903200_R9"},{"key":"2025102817560903200_R10","unstructured":"B\u00e5ge         R.                                       Petyim         S.                                       Larsson         B.                                       Gustafsson         H.                                       Forsberg         M.                                       Rodr\u00edguez-Mart\u00ednez         H.                           2001      b      Repeated OPU on day 0 to 12 of the cycle for the use of dairy heifers as both oocyte donors and embryo recipients.                                    Rodr\u00edguez-Mart\u00ednez         H.                           50      Proceedings of the 5th Conference of ESDAR 13\u201315 September 2001      Vienna, Austria.             Blackwell       Edinburgh, UK.            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