The cause of repeat breeding syndrome is often difficult to explain in dairy heifers with no clinical abnormalities. The aim of the present experiment was to determine the effect of follicular fluid obtained from the preovulatory follicle of repeat breeder heifers on maturation of @entity291 oocytes in vitro. Holstein virgin heifers either with normal fertility (VH, n=5) or @entity19998 ( @entity19998 , n=5) were used in the present experiment. The @entity19998 heifers had a history of at least 5 unsuccessful consequent artificial breeding. The reason for using such @entity19998 heifers was to exclude the possibility of the presence of usual causes of @entity249 in heifers. Oestrus cycles of all heifers were synchronized using 2 injections of PGF2a 11 days apart. Six to 12h after oestrus detection, clear follicular fluid samples from the ovulatory follicles were collected transrectally using a long fine-needle covered by a hard plastic tube. Follicular fluid samples were pooled, centrifuged, and frozen until used in the maturation medium. A total of 483 good or excellent quality @entity291 cumulus-oocytes complexes (COC) were obtained from 2 to 6mm follicles in diameter from slaughterhouse ovaries and randomly allocated in 3 groups; in group 1 (control, n=180), oocytes were cultured in TCM-199 supplemented with 10% heat-treated fetal calf serum and hormones (5IUmL(-1) of hCG plus 0.1IUmL(-1) of rFSH); in group 2 (n=126), oocytes were cultured in TCM-199 supplemented with 10% filtered follicular fluid of VH without hormones; in group 3 (n=177), oocytes were cultured in TCM-199 supplemented with 10% filtered follicular fluid of @entity19998 heifers without hormones. All oocytes were cultured for 24h at 39  C in an atmosphere of 5% @entity515 under 90% humidity. At the end of maturation, the degree of cumulus expansion was evaluated and scored under a stereomicroscope. Then, oocytes were mechanically denuded using 3% @entity4958 and repeated pipetting and were fixed in @entity1068 / @entity1543 (3:1) for 24h. The oocytes were subsequently stained with 1% @entity68571 and evaluated for meiotic resumption. Proportions were statistically analysed using a Chi-squared test (significant at P<0.05; SPSS program, 11.5). The percentages of fully expanded COC differed among groups (P<0.001). The maturation rate (MII stage) was 83% (150/180) in oocytes that were cultured in the presence of FCS as the control group. However, a reduction in the maturation rate was observed when oocytes were cultured either in VH follicular fluid (71.4%, 90/126; P<0.01) or @entity19998 follicular fluid (59.3%, 105/177; P<0.001) compared to the control group. The percentages of matured oocytes were also different between VH and @entity19998 follicular fluid (71.4 v. 59.3%; P<0.01, respectively). In conclusion, the quality of follicular fluid of the preovulatory follicles of repeat breeder heifers is lower than that of the virgin heifers with normal fertility. This may explain the cause of the low fertility in some repeat breeder Holstein heifers.

294 effects of follicular fluid obtained from repeat breeder dairy heifer on maturation of XXXX oocytes in vitro.

@entity4958 :: ('MESH:C102006', 'Chemical') :: ['sodium citrate'] @entity249 :: ('MESH:D007246', 'Disease') :: ['infertility'] @entity68571 :: ('MESH:C018437', 'Chemical') :: ['aceto-orcein'] @entity19998 :: ('MESH:D001716', 'Disease') :: ['RB', 'repeat breeder syndrome'] @entity515 :: ('CHEBI:29334', 'Chemical') :: ['CO2'] @entity1068 :: ('MESH:D000431', 'Chemical') :: ['ethanol'] @entity291 :: ('9913', 'Species') :: ['bovine'] @entity1543 :: ('MESH:D019342', 'Chemical') :: ['acetic acid']
@entity291 :: (9913,Species) :: ['bovine']
