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OOCYTE QUALITY IN REPEAT-BREEDER DAIRY HEIFERS AND EFFECTS OF OPU ON REPRODUCTIVE PERFORMANCE R Båge1, S Petyim1, B Larsson1, T Hallap1, AS Bergqvist1, H Gustafsson2 and H Rodríguez-Martínez1; 1SLU, Uppsala, Sweden and 2Swedish Dairy Association, Eskilstuna, Sweden. Repeat-breeder heifers (RBH) deviate from normal considering hormonal interplay during estrus, with effects on estrus and ovulation (Båge R et al, Theriogenology 2002;57:2257-2269). This study evaluated the effect of repeated ovum pick-up (OPU) on RBH characteristics. The aims were to study 1) effects of OPU on estrous cyclicity, follicle development and oocyte recovery rate, 2) IVM and IVF competence and oocyte morphology after IVM, and 3) carry-over effects on fertility. Ten Swedish red and white-breed heifers were used: defined RBH, (n=5, average age 3.5 yrs, 3 AIs with returns to estrus within normal inter-estrous intervals) and virgin heifers (VH, controls, n=5, average age 2.7 yrs). Oocytes were retrieved by OPU performed twice weekly during 4 to 6 consecutive estrous cycles. OPU was restricted to the first 12 cycle days, starting after spontaneous ovulation of the pre-ovulatory follicle had occurred. A total of 269 RBH oocytes and 174 VH oocytes were collected. Oocytes were quality scored prior to conventional IVM and IVF. Ten immature and ten IVM oocytes from either category were fixed for morphology. Nuclear and mitochondrial changes after IVM were studied by laser confocal microscopy (LSM 510, Zeiss, Oberkuchen, Germany) after staining with propidium iodide and Mitotracker Green (Molecular Probes, Leiden, the Netherlands). Ultrastructure was studied by TEM (JEM-1230, JEOL Ltd., Akishima, Japan). At first estrus after OPU, the heifers were artificially inseminated. Plasma progesterone concentrations were analysed by RIA (Coat-A-Count®, Diagnostic Products Corporation, Los Angeles, CA) on cycle D0 (onset of standing estrus), 6, 12 and 16, plus D21 and 23 after AI. Pregnancy was confirmed by ultrasonography 30 days after AI. Frequency distributions were compared by Chi-square test, and a Mann-Whitney test or Wilcoxon Signed rank test were used for group-wise comparisons (Minitab software, Minitab® Release 10.2, Minitab Inc., PA). During OPU, RBH progesterone concentrations were higher (P

Nyckelord

artificial insemination; bovine; confocal microscopy; electron microscopy; infertility; oocyte quality; progesterone

Publicerad i

Theriogenology
2003, volym: 59, nummer: 1
Utgivare: Nagai Takashi, Piedrahita Jorge

Konferens

Annual Conference of the International Embryo Transfer Society, IETS

SLU författare

UKÄ forskningsämne

Klinisk vetenskap

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/236