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ABSTRACT: Two experiments were designed to evaluate the effect of different insemination times (12 and 24h or 18 and 30h) and different types of semen (sex-sorted or non-sorted sperm) on embryo production in Nelore (Bos indicus) and Holstein (Bos taurus) superstimulated donors. In the first experiment, hormonal superstimulation of ovarian follicular development in Nelore donors (n=71) was performed in randomly allocated animals to one of the three treatment groups, and they were inseminated at 12 and 24h after an ovulatory stimulus with pLH treatment was applied, either with sex-sorted (4.2×10(6) sperm/insemination; S12/24; n=17) or non-sorted sperm (20×10(6) sperm/insemination; NS12/24; n=18), or they were inseminated at 18 and 30h using sex-sorted sperm (4.2×10(6) sperm/insemination; S18/30; n=19). A greater number of transferable embryos were found when sex-sorted sperm was used to inseminate the animals at 18 and 30h (4.5±3.0) compared to insemination at 12 and 24h (2.4±1.8; P<0.001). However, a greater embryo production (6.8±2.6) was obtained with non-sorted sperm. In the second experiment, the same insemination times and semen types were used in lactating high-production Holstein cows (n=12). A crossover design was employed in this trial. A lesser embryo production (P=0.007) was found in Holstein donors that were inseminated using sex-sorted sperm at 12 and 24h (4.6±3.0) compared to non-sorted sperm (8.7±2.8). However, intermediate results were obtained when the inseminations with sex-sorted sperm were performed at 18 and 30h (6.4±3.1). These results supported the current hypothesis that it is possible to improve embryo production using sex-sorted sperm in B. indicus and B. taurus superstimulated donors when the inseminations are performed near the same time as time-synchronized ovulations. However, the embryo production for timed artificial insemination (TAI) with sex-sorted sperm was still less than the production with non-sorted sperm.
Animal reproduction science 08/2011; 127(3-4):148-53. · 1.56 Impact Factor
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L U Gimenes,
N A T Carvalho,
M F Sá Filho,
F S Vannucci, J R S Torres-Júnior,
H Ayres,
R M Ferreira,
L A Trinca,
E S Sartorelli,
C M Barros,
M P Beltran,
G P Nogueira,
R J Mapletoft,
P S Baruselli
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ABSTRACT: The objectives of this study were to determine the interval from ovulation to deviation and the diameter of the dominant (DF) and largest subordinate (SF) follicles at deviation in buffalo (Bubalus bubalis) heifers. Two methods of evaluation (observed vs. calculated) were used. FSH and LH profiles encompassing follicle deviation (Experiment 1), and the follicular diameter when the DF acquired ovulatory capacity (Experiment 2) were also determined. The time of deviation and the diameter of the DF and the largest SF at deviation did not differ between observed and calculated methods. Overall, follicle deviation occurred 2.6 ± 0.2d (mean ± SEM) after ovulation, and the diameters of the DF and SF at deviation were 7.2 ± 0.2 and 6.4 ± 0.2mm, respectively. No changes in plasma levels of FSH or LH were observed (P=0.32 and P=0.96, respectively). Experiment 2 was conducted in two phases according to the diameter of the DF during the first wave of follicular development at the time of LH challenge (25mg of pLH). In the first phase, follicles ranging from 5.0 to 6.0mm (n=7), 6.1 to 7.0mm (n=11), or 7.1 to 8.0mm (n=9) were used, and in the second phase, follicles ranging from 7.0 to 8.4mm (n=10), 8.5 to 10.0mm (n=10), or 10.1 to 12.0mm (n=9) of diameter were used. After the pLH treatment, the DF was monitored by ultrasonography every 12h for 48h. No ovulations occurred in heifers in the first phase. However, in the second phase, an effect of follicular diameter was observed on ovulation rate [7.0-8.4mm (0.0%, 0/10), 8.5-10.0mm (50.0%, 5/10), and 10.0-12.0mm (55.6%, 5/9)]. In summary, follicle deviation occurred 2.6d after ovulation in buffalo (B. bubalis) heifers, when the diameters of the DF and SF were 7.2 and 6.4mm, respectively. No significant changes in plasma concentrations of FSH or LH were detected. Finally, the acquisition of ovulatory capacity occurred when the DF reached 8.5mm in diameter.
Animal reproduction science 02/2011; 123(3-4):175-9. · 1.56 Impact Factor
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ABSTRACT: A total of 177 Nelore heifers were examined by ultrasonography to determine the presence or absence of a corpus luteum (CL) and received a 3mg norgestomet ear implant plus 2mg of estradiol benzoate i.m. On Day 8, implants were removed and 150 microg of d-cloprostenol i.m. was administered. At the time of norgestomet implant removal, heifers with or without CL at the time of initiating treatment were assigned equally and by replicate to be treated with 0IU (n=87) or 400IU (n=90) eCG i.m. All heifers received 1mg of EB i.m. on Day 9 and were submitted to fixed-time artificial insemination (FTAI) 30-34h later. The addition of eCG increased the diameter of the largest follicle (LF) at FTAI (10.6+/-0.2mm vs. 9.5+/-0.2mm; P=0.003; mean+/-SEM), the final growth rate of the LF (1.14+/-0.1mm/day vs. 0.64+/-0.1mm/day; P=0.0009), ovulation rate [94.4% (85/90) vs. 73.6% (64/87); P=0.0006], the diameter of the CL at Day 15 (15.5+/-0.3mm vs. 13.8+/-0.3mm; P=0.0002), serum concentrations of progesterone 5 days after FTAI (6.6+/-1.0 ng/ml vs. 3.6+/-0.7ng/ml; P=0.0009), and pregnancy per AI [P/AI; 50.0% (45/90) vs. 36.8% (32/87); P=0.04]. The absence of a CL at the beginning of the treatment negatively influenced the P/AI [30.2% (16/53) vs. 49.2% (61/124); P=0.01]. Therefore, the presence of a CL (and/or onset of puberty) must be considered in setting up FTAI programs in heifers. In addition, eCG may be an important tool for the enhancement of follicular growth, ovulation, size and function of the subsequent CL, and pregnancy rates in progestin-based FTAI protocols in Bos indicus heifers.
Animal reproduction science 10/2009; 118(2-4):182-7. · 1.56 Impact Factor
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L U Gimenes,
M F Sá Filho,
N A T Carvalho, J R S Torres-Júnior,
A H Souza,
E H Madureira,
L A Trinca,
E S Sartorelli,
C M Barros,
J B P Carvalho,
R J Mapletoft,
P S Baruselli
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ABSTRACT: The objectives of Experiment 1 were to determine the interval from ovulation to deviation, and diameter of the dominant follicle (DF) and largest subordinate follicle (SF) at deviation in Nelore (Bos indicus) heifers by two methods (observed and calculated). Heifers (n = 12) were examined ultrasonographically every 12 h from ovulation (Day 0) to Day 5. The time of deviation and diameter of the DF and largest SF at deviation did not differ (P>0.05) between observed and calculated methods. Overall, deviation occurred 2.5+/-0.2 d (mean +/- S.E.M.) after ovulation, and diameters for DF and largest SF at deviation were 6.2+/-0.2 and 5.9 +/- 0.2 mm, respectively. Experiment 2 was designed to determine the size at which the DF acquires ovulatory capacity in B. indicus heifers. Twenty-nine heifers were monitored every 24 h by ultrasonography, from ovulation until the DF reached diameters of 7.0-8.4 mm (n=9), 8.5-10.0 mm (n=10), or >10.0 mm (n=10). At that time, heifers were treated with 25 mg of pLH and monitored by ultrasonography every 12 h for 48 h. Ovulation occurred in 3 of 9, 8 of 10, and 9 of 10 heifers, respectively (P<0.05). In summary, there was no significant difference between observed and calculated methods of determining the beginning of follicle deviation. Deviation occurred 2.5 d after ovulation when the DF reached 6.2 mm, and ovulatory capacity was acquired by DF as small as 7.0 mm.
Theriogenology 05/2008; 69(7):852-8. · 1.96 Impact Factor
