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  • Küçük Resim
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    Conception rate following timed artificial insemination protocols in dairy heifers synchronised by PGF2? and GnRH
    (ANKARA UNIV PRESS, 2011) Tasdemir, Umut; Yilmazbas-Mecitoglu, Gulnaz; Keskin, Abdulkadir; Karakaya, Ebru; Celik, Yakup; Guzeloglu, Aydin; Gumen, Ahmet
    This study aimed to develop a timed artificial insemination (TAI) protocol using PGF2? and GnRH with acceptable pregnancy rate in dairy heifers. Dairy heifers (n=290), aged between 13 and 26 months (mean 16.1 months), were used in this study. Heifers were synchronized with two PGF(2 alpha) administrations by 14 d intervals. After the second PGF(2 alpha), heifers were randomly assigned into two groups. In Group 1 (n=155), GnRH was given at 56h following 2nd PGF(2 alpha) and TAI was performed at 16-18h after the GnRH. In Group 2 (n=135), GnRH was administered at 72h after 2nd PGF(2 alpha), at the time of TAI. Ultrasonography was performed at both PGF(2 alpha) administrations to determine cyclicity, at the time of TAI to measure ovulatory follicle size, 7 d after TAI to determine ovulation, 31 and 62 d post-AI to determine pregnancy. Ovulatory follicle size at the time of TAI was not significantly different between groups (12.8 +/- 1.6 mm and 13.2 +/- 1.8 mm in group 1 and 2, respectively). Synchronization rate was similar in group 1 (85.2%;132/155) and in group 2 (91.1%;123/135). Conception rate (CR) at 31 d was not different in group 1(59.8%;79/132) and in group 2 (55.3%;68/123). Embryonic loss (7.6%; 6/79 and 7.4%; 5/68 in group 1 and 2 respectively) was not different. Gender ratio of the calves was found different between groups. Proportion of the female calves born were higher (P=0.03) in group 1 (63.3%; 38/60) than in group 2 (42.0%; 21/50). In conclusion, both protocols can be used in order to eliminate estrous detection in large dairy herds. Although GnRH administration at the time of TAI was found to be useful to reduce handling of heifers, GnRH can be applied 16-18 h before Alto achive higher female calves ratio in large dairy farms.
  • Küçük Resim Yok
    Öğe
    Leptin and IGF-I improve bovine embryo quality in vitro
    (BRAZILIAN COLL ANIMAL REPRODUCTION, 2017) Kaya, Abdullah; Sagirkaya, Hakan; Misirlioglu, Muge; Gumen, Ahmet; Parrish, John J.; Memili, Erdogan
    The in vitro embryo culture systems need further improvement to enhance the efficiency of bovine embryo production. Growth factors play key roles in embryo production and quality. The objective of this study was to define the effects of leptin, insulin-like growth factor-1 (IGF-1), and their combination on embryonic development, apoptosis, and expression profiles of a panel of developmentally important genes during 8-day embryo culture. The oocytes were aspirated from slaughterhouse ovaries of mixed breed cows. Following IVM/IVF presumptive zygotes were obtained. To accomplish this objective, presumptive zygotes (16-18 h post-insemination) were cultured in vitro as control (no supplementation, n = 349), 5 ng/ml leptin (Group I, n = 322), 100 ng/ml IGF-1 (Group II, n = 347), and 5 ng/ml leptin and 100 ng/ml IGF-1 (Group III, n = 360). All groups were supplemented with 10% fetal calf serum (FCS) on Day 4, and blastocysts were harvested on day 8. The DNA-fragmented nuclei of blastocyst were determined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and expression profiles of a panel of developmentally important genes were assayed by real-time polymerase chain reaction (RT-PCR). The cleavage rate and embryo development to 8-16 cell stage were higher in groups II and III as compared to control (P < 0.05), respectively. Percentage of blastocyst and mean cell numbers per blastocyst did not differ among the groups. Addition of IGF-I and/or combination with leptin decreased the number of nuclei with fragmented DNA (P < 0.01) as compared to the control group. Although the expression of glucose transporter 1 (Glut1), desmosomal glycoprotein desmocollin III (DcIII), and insulin like growth factor 2 receptor (Igf2r) transcripts did not change among the groups, interferon-tau (IF-tau) and DNA methyltransferase 3A (Dnmt3a) were down-regulated in group II while heat shock protein-70 (Hsp70) and IF-tau were up regulated in group III. Results indicate that addition of IGF-I in culture media improved the cleavage rate; combination with leptin also improved the development rates to 8-16-cell-stage embryos, decreased the TUNEL-positive nuclei, and caused alterations in the amounts of transcripts for the developmentally important genes assayed.