News briefing： The purpose of this study was to evaluate the feasibility of preselection with higher or lower response to superovulation. After long-term progesterone treatment, twenty Saneng goats were treated with horse chorionic gonadotropin (eCG) of 800 IU.
The purpose of this study was to evaluate the feasibility of preselection with higher or lower response to superovulation. After long-term progesterone treatment, twenty Saneng goats were treated with horse chorionic gonadotropin (eCG) of 800 IU. Fourteen days later, the second progesterone treatment was performed in combination with multiple doses of follicle stimulating hormone (FSH) (5 IU/kg FSH, six doses were reduced between 4 and 6 days in the treatment phase). The status of follicles at the beginning of superovulation and the number of corpus luteum (CL) at the beginning of oestrus and the seventh day of the oestrus cycle were evaluated by transrectal ultrasound.
The results showed that compared with FSH treatment, eCG treatment showed significantly lower CL number (p<0.05). Four regression analysis can explain the relationship between the number of CL and the response of the two treatments (r2=0.50; p<0.05). After treatment, 70% of the dose (14, 20) maintained the same ovulation response (high or low). Kappa（ κ= 0.40; P<0.05) and Spearman (rs=0.39; p=0.08) coefficients showed the relationship between the two treatments. As for follicular status, the number of small follicles (r=0.71; r2=0.47; p<0.01) and total follicles (r=0.60; p<0.01) were significantly related to the number of CL in eCG treatment and the first FSH treatment.
In addition, the study found that there was a negative correlation between the presence of large follicles and the number of CL when treated with eCG (r=-0.44; p<0.05), but this did not occur in FSH (p>0.05). In a word, the screening test of eCG treatment has the potential to identify Saneng milk goats, and can better respond to the superovulation program involving FSH. In addition, the study highlighted the importance of using ultrasound to evaluate the follicular status at the beginning of superovulation treatment involving FSH, and to identify potential goat donors with high ovulation response in embryo transfer engineering.
