Browsing by Author "Bilen, Ebru Karakaya"
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Item Conception rate following timed artificial insemination protocols in dairy heifers synchronised by PGF(2 alpha) and GnRH(Ankara Üniversitesi, 2011) Taşdemir, Umut; Çelik, Yakup; Güzeloǧlu, Aydın; Mecitoğlu, Gülnaz Yılmazbaş; Keskin, Abdülkadir; Bilen, Ebru Karakaya; Gümen, Ahmet; Uludağ Üniversitesi/Veterinerlik Fakültesi/Kadın Hastalıkları ve Doğum Anabilim Dalı.; 0000-0003-2817-3221; AAH-3831-2021; AAH-1406-2021; AAG-4440-2019; 36457964000; 24473229800; 36457784500; 6602393069This study aimed to develop a timed artificial insemination (TAI) protocol using PGF(2 alpha) 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.Publication Effects of beta-carotene administration on fertility in lactating dairy cows(Agricultural Research Communication Centre, 2021-02-01) Bilen, Ebru Karakaya; ; Mecitoglu, Gulnaz Yilmazbas; MECİTOĞLU, GÜLNAZ; Bursa Uludağ Üniversitesi/Veterinerlik Fakültesi.; 0000-0003-2817-3221; AAG-4440-2019Background: Beta-(beta-) carotene, is the precursor to vitamin A, in particular, has some potential benefits on reproduction. The main objective of this study was to investigate the efficacy of beta-carotene administration on fertility following either prostaglandin F2 alpha (PGF) induced estrus or Ovsynch protocol in lactating dairy cows.Methods: Cows with at 47 +/- 3 postpartum days were divided into two groups: beta-carotene group (beta C, n=139) was treated with injectable beta-carotene while untreated cows served as control (CON, n=227). In both groups, PGF was administered and heatmount detectors were applied at 54 +/- 3 days postpartum. Cows detected in estrus after PGF were inseminated. Cows that had not been detected in estrus were divided into two groups 7 days after PGF administration; beta C-ovs (n=137) and CON-OVS (n=89). Ovsynch protocol was initiated 4 days after beta-carotene administration.Result: The estrus detection rate was similar between the beta C and CON groups (P = 0.19). Pregnancy per AI (P/AI) on d 31 was also similar between groups (P = 0.93). In the Ovsynch protocol, ovulation to the first GnRH and ovulatory follicle diameter at the time of insemination did not differ between groups. No difference was observed in P/AI at d 31 (P = 0.13). The results of this study indicated that beta-carotene administration had no effect on fertility either PGF induced estrus or Ovsynch protocol in dairy cows.Item Effects of GnRH, PGF2α and oxytocin treatments on conception rate at the time of artificial insemination in lactating dairy cows(Czech Academy Agricultural Sciences, 2011) Çevik, Samet; Gümen, Ahmet; Keskin, Abdülkadir; Mecitoğlu, Gülnaz Yılmazbaş; Bilen, Ebru Karakaya; Balcı, Faruk; Uludağ Üniversitesi/Veterinerlik Fakültesi/Kadın Hastalıkları ve Doğum Anabilim Dalı.; Uludağ Üniversitesi/Veterinerlik Fakültesi/Zootekni ve Hayvan Besleme Bölümü.; 0000-0003-2817-3221; AAH-1406-2021; AAG-4440-2019; AAH-3831-2021; 6602393069; 24473229800; 36457964000; 36457784500; 16062981700In several studies, hormones such as gonadotropin-releasing hormone (GnRH), prostaglandins and oxytocin were used to increase pregnancy rate by inducing ovulation and improving the sperm transport in the female reproductive tract in lactating dairy cattle. The objective of this study was to compare the effects of GnRH, prostaglandin F-2 alpha (PGF(2 alpha)) and oxytocin treatments at the time of artificial insemination (AI) after spontaneous oestrus on the conception rate (CR) of lactating dairy cows. Oestrus was detected by visual observations by experienced personnel. All cows (n = 430, 308 Holstein-Frisian and 122 Swedish-Red dairy cows) were inseminated based on the am/pm rule by veterinarians of the farm. After AI, cows were alternately assigned to one of the four treatment groups: (1) GnRH (n = 113); (2) PGF(2 alpha) (n = 106); (3) oxytocin (n = 106) and (4) non-treated control (n = 105). Pregnancy diagnosis was performed 28-34 and 58-64 days post-insemination by transrectal ultrasonography. Conception rates on days 28-34 and 58-64 were not different among GnRH (46.0%; 52/113 and 44.3%; 50/113), PGF(2 alpha) (37.7%; 40/106 and 35.9%; 38/106) and control (49.5%; 52/105 and 47.6%; 50/105) groups. However, conception rates were lower (P = 0.02) in oxytocin (31.1%; 33/106 and 30.2%; 32/106) than in GnRH and control groups on days 28-34 and 58-64. Other covariant factors, such as milk production, days in milk (DIM), breed, parity, service number did not affect the conception rate. Thus, there were no beneficial effects of treatments with GnRH and PGF(2 alpha) at the time of AI, and oxytocin had an adverse effect on CR in lactating dairy cows in this study.