The purpose of this experiment was to determine the influence of the ovarian status on the initiation day of superovulation (d 0) on superovulatory responses in terms of the number of large follicles (≥7mm) at estrus (d 4) and CL 7 days after estrus (d 11). Ultrasonography was performed on d 0, 4 and 11of the experiment. Animals conventionally superovulated (400 mg Folltropin-V) between d 8 to 12 of the estrous cycles and 102 superovulation cycles were considered in the present experiment. Data were analyzed using GLM procedure of the SAS. In these cases, the number of follicles was determined in each of the 2 studied classes (SF, 4 to 6 mm; and LF, ≥7mm) on d 0. Subsequently, each of these classes was divided into two subgroups (Low, High) based on the number of follicles observed on d 0 (Table 1). The number of LF at estrus in each of the 2 studied classes (Low vs. High) were (13.02±1.02 vs. 19.7±1.69, p<0.01; and 16.23±1.59 vs. 14.75±1.48, p>0.1) and the number of CL on d 11 were (9.75±0.57 vs. 12.75±0.98, p<0.01; 10.91±0.8 vs. 10.85±0.65, p>0.1). Therefore, the ovarian status on d 0 in terms of the number of SF affected the number of LF (d 4) and CL (d 11). In addition, the number of superovulatory cycles with low number of SF was 2 times more than the ones with a high number of SF on d 0; also 49 out of 102 superovulatory cycles had at least 2 LF on the initiation day of superovulation (Table 1). These results suggested that follicular puncture 1–2 days before a conventional superovulation treatment may increase the superovulatory responses.
The present study considers the right versus the left ovarian responses to the different doses of eCG treatment in ewe. The estrous cycles of 32 adult Shall Iranian ewes were synchronized by CIDR during breeding period. At the time of CIDR removal, 0 (n = 8), 450 (n = 8), 550 (n = 8) and 650 (n = 8) IU of eCG (Intervet, Booxmer, Netherlands) was administered to ewes. The number of large follicles (> 3 mm, LF) and CL in the right and left ovaries was monitored by transrectal ultrasonography on the day of estrus and 6 days later. In another analysing view, all ewes (n = 32) were set into 3 groups. Following superovulation, groups A and D ewes had at least one extra large follicle and CL, respectively, in their right ovary than that of the left one. Group B and E had the opposite position and group C and F had equal LF in their ovaries. The data were analysed by GLM procedure of SAS. The mean number of LF in the right (2.35 ± 0.14) was higher (P < 0.001) in comparison to the left (1.42 ± 0.14) ovaries in all treatment groups. Also, the mean number of LF in the right was higher (P < 0.05) than that in the left ovaries between every treatment group. In addition, the mean number of CL in the right (1.92 ± 0.47) was higher (P < 0.05) in comparison to the left (1.33 ± 0.25) ovaries in all treatment groups. Furthermore, in the other analysis, we observed 62.5% of the ewes were in group A (n = 20) which was a higher (P < 0.001) percentage compared to group B (n = 4, 12.5%) and group C (n = 8, 25%). Also, it is observed that 44% of the ewes were set into group D (n = 16) (the right ovary had at least one CL extra in comparison with the left ovary) which was a higher (P < 0.05) percentage compared to groups E and F; and that both groups had equal number of ewes. The results suggest that the greater responses of follicular development occur in the right ovaries after eCG treatment in Shall Iranian ewes.
The objective of this experiment was to determine the influence of the ovarian status on the initiation day of superovulation (day 14) on superovulatory response in terms of the number of ovulatory follicles (F, ≥4mm) at estrus (day 16). Estrous cycles of 50 Shall Iranian ewes were synchronized by CIDR. The day of CIDR insertion was considered as the starting point of the experiment (day 0). At the time of CIDR removal (day 14), 650 IU of eCG was administered to ewes. Ultrasonography was performed on days 14 and 16. Data were analyzed by means of the GLM procedure of the SAS. In these cases, the number of follicles were determined in each of the three studied classes (<2, 2 to 4, and ≥4 mm) on day 14. Subsequently, each of these classes was divided into two subgroups (Low, High) based on the number of follicles observed on day 14 (Table 1). The number of large follicles at estrus in each of the three studied classes were (3.96±0.28 vs. 4.78±0.26, p<0.05; 4.31±0.35 vs. 4.41±0.24, p>0.05; and 4.50±0.23 vs. 4.07±0.37, p>0.05) respectively. The number of medium and large follicles on day 14 did not affect the superovulatory response. However, the high number of small follicles on the initiation day of superovulation increased the number of ovulatory follicles at estrus. Since, 23 out of 50 ewes had a low number of small follicles on day 14 (Table 1), which may suggest that an injection of FSH 1-2 days before initiation of eCG treatment enhance the superovulatory response.
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