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    Effects of estrous cycle stage and transport temperature of ovaries on in vitro maturation of canine oocytes
    (Elsevier Science Bv, 2010) Evecen, Mithat; Cirit, Uemuet; Demir, Kamber; Ozdas, Ozen Banu; Tas, Muzaffer; Birler, Sema; Pabuccuoglu, Serhat
    Unlike other domestic animals, in vitro maturation (IVM) of canine oocytes still has limited success. The present study investigated the effects of estrous cycle stage and transport temperature of ovaries on in vitro maturation of canine oocytes. The donor bitches were categorized into three groups based on stage of estrus cycle: follicular (proestrus or estrous), luteal (diestrus) and anestrus. One ovary of each pair collected from 39 mature bitches was transported in Phosphate Buffer Saline (PBS) at 4 degrees C while the other was transported at 37 degrees C. A total of 1138 Grade I COCs obtained from all ovaries were grouped and matured in modified synthetic oviduct fluid (mSOF) supplemented with follicle stimulating hormone (FSH), luteinizing hormone (LH), essential and non-essential amino acids at 38.5 degrees C in a humidified 5% CO2, 5% O-2, and 90% N-2 atmosphere for 72 h. The nuclear maturation rates were evaluated by aceto-orcein staining. Oocytes harvested from follicular and luteal ovaries have a significantly higher maturation rates (MI+MII) than the oocytes from anestrual ovaries in the 37 degrees C group (p<0.05). However, oocytes harvested from anestrual ovaries transported at 4 degrees C had the highest maturation (MI + MII) rate, and the difference between anestrual and luteal ovary groups was significant (p < 0.05). The oocytes from anestrual ovaries transported at 4 degrees C have significantly higher maturation rates than those transported at 37 degrees C (p < 0.0001). However, the transport temperature (37 or 4 degrees C) did not significantly affect the maturation (MI + MII) rates of oocytes harvested from the luteal (p = 0.61) and follicular (p = 0.48) stage ovaries. It can be concluded from this study that (1) both transport temperature and transport temperature x estrus cycle stage interaction effected the maturation rates, while estrus cycle stage alone did not, and (2) transporting canine ovaries at 4 degrees C can improve in vitro maturation rates in oocytes harvested from anestrous ovaries. (C) 2009 Elsevier B.V. All rights reserved.
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    Evaluation of short estrus synchronization methods in dairy cows
    (Elsevier, 2008) Cirit, Uemuet; Bacinoglu, Suleyman; Tas, Muzaffer; Demir, Kamber; Bas, Ahmet; Ak, Kemal; Ileri, Irfan Kamuran
    In the present study, two new short estrus synchronization methods have been developed for lactating dairy cows. The study was completed in three consecutive phases. In experiment (Exp) 1, 32 cows, that were not detected in estrus since calving between the 50th and 84th post-partum days, were treated with PGF2 alpha (PGF, D-Cloprostenol, 0.150 mg), estradiol propionate (EP, 2 mg) and GnRH (lecirelina, 50 mu g) at 24 h intervals, respectively, and timed artificial insemination (TAI) was performed 48 h after PGF. Different from Exp 1, EP and GnRH were given at 48 and 60 h, respectively after PGF in Exp 2 (n = 20), instead of 24 and 48 h. Ovulations were investigated by ultrasound for 7 days starting from the day of PGF treatment, and ovulation rates were compared with the ones obtained in Exp 1. In Exp 3, cows were given the same treatments as Exp 2, but treatments started at certain estrus stages. Cows detected in estrus and with a confirmed ovulation (n = 27) after the second PGF given 11 days apart were assigned to three treatment groups. Treatment was initiated at Day 3 (group metestrus, n = 9), Day 12 (group diestrus, n = 9) and Day 18 (group proestrus, n = 9) after ovulation. All cows included in Exp 3 were TAI between 16 and 20 h after GnRH treatment. In Exp 2 and 3, blood samples were obtained once every 2 days, starting from Day 0 to the 10th day after GnRH injection, and once every 4 days between the 10th and the 22nd days after GnRH to examine post-treatment luteal development. During the study, animals exhibiting natural estrus were inseminated and served as controls (n = 85). The rate of estrus was found to be significantly higher in cows with an active corpus luteum (CL) at the start of Exp 1 (72.7% vs. 30.0%, P < 0.05) and the pregnancy rate tended to be higher than cows without an active CL (40.9% vs. 10.0%, P = 0.08). Compared to those in Exp 1, cows in Exp 2 had higher rates of synchronized ovulation (94.1% vs. 59.1%, P = 0.013), In Exp 3, estrus (P < 0.001) and pregnancy rates (P = 0.01) were found to be significantly higher in cows in the proestrus group than in those in the metestrus group. Comparable pregnancy rates were obtained from the first and second inseminations in Exp 1 and 3 with results from those inseminated at natural estrus (P > 0.05). It was concluded from the study that the treatment in Exp 1 and 3 could result in comparable pregnancy rates after timed Al of lactating dairy cows at random stages of the estrus cycle relating to those inseminated at natural estrus, but the stage of the estrus cycle can have significant effects on pregnancy rates. (C) 2007 Elsevier B.V. All rights reserved.
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    Use of a decreased dose of cabergoline to treat secondary anoestrus in bitches
    (Natl Veterinary Research Inst, 2007) Cirit, Uemuet; Bacinoglu, Suleyman; Tas, Muzaffer; Alkan, Serhat
    The aim of the study was to determine whether a dose (0.6 mu g/kg/d) quite lower than the prolactin-lowering dose of cabergoline, prepared for humans, would be a safe and effective method for the stimulation of oestrus in bitches at secondary anoestrus or late anoestrus. Twenty-four pure blood bitches from various breeds were used in the study at their already determined periods of anoestrus. The treatment group included bitches at late and prolonged anoestrus. Eight bitches that had not shown any signs of oestrus for the preceding 370 to 485 d formed the secondary anoestrus group. Eight of the 16 bitches at late anoestrus (days 165-280) have accomplished the late anoestrus group and another 8 have been chosen randomly for the control group (untreated). Cabergoline was orally administrated until day 2 after the onset of pro-oestrus or for a maximum of 42 d. Blood samples were taken daily from each bitch during the first 5 d of behavioural oestrus to measure progesterone concentrations. In the secondary anoestrus and late anoestrus groups, oestrus was induced on days 4-14 and 12-45 at a ratio of 75.0% (6/8) and 87.5% (7/8), respectively.. The mean pro-oestrus and behavioural oestrus durations, serum progesterone concentrations on day 5 of oestrus, ovulation rates, pregnancy rates, and the mean litter sizes in secondary anoestrus, late anoestrus, and control groups were found to be similar. None of the dogs had any adverse gastrointestinal effects associated with cabergoline administration. The results of the present study suggest that the administration of 0.6 mu g/kg/d of cabergoline is a safe and effective treatment for secondary anoestrus in bitches.