Farmacopuntura na administração de subdose de gonadotrofina coriônica equina em protocolo de inseminação artificial em tempo fixo em bovinos de corte

Abstract

The objective of the study was to evaluate whether the use of pharmacopuncture enhances the effect of a subdose of equine chorionic gonadotropin (eCG) in a fixed-time artificial insemination (TAI) protocol for cattle. In the first experiment, 34 cows were used to evaluate ovarian follicular dynamics and luteal function. A completely randomized design was used. The TAI protocol began on day 0 (D0) with the insertion of an intravaginal progesterone implant (P4) and estradiol benzoate, intramuscularly (IM). After removal of the implant (D9), the females received prostaglandin (F2 ) and estradiol cypionate IM and were divided into three treatments: T1 (n=12) - 300 IU of eCG IM; T2 (n=12) - 60 IU of eCG (20% of the T1 dose) at the Hou Hai acupoint; and T3 (n=10) - 60 IU of eCG, in a false acupoint, IM. Inseminations were performed on D11. Ovarian follicular dynamics were evaluated at the time of implant removal until ovulation to determine the follicular growth rate, diameter and area of the ovulatory follicle, ovulatory moment and rate, blood perfusion area of the ovulatory follicle wall, and serum P4 dosage. on D9. On D20, corpus luteum (CL) diameter and area, CL blood perfusion area, and blood collection were measured to determine serum P4 concentrations. There was no difference between treatments for the variables follicle diameter at device removal and at the time of ovulation, in the vascularization area on the day of device removal, at the time of AI and at the time of ovulation, at the time and rate of ovulation and serum P4 levels on the day of AI. On the other hand, a statistical difference was observed for follicle diameter on the day of insemination (T1=10.38; T2=12.54 and T3=11.25 mm), follicle area at the time of AI (T1=3.90; T2 =5.93; T3= 5.01 cm2), ovulatory follicle area (T1= 4.07; T2= 5.77; T3=5.11 cm2) and follicular growth rate (T1=0.183; T2=0.191 and T3=0.265 mm/day). In the CL morphofunctional parameters there was a difference in the percentage of CL vascularization (T1=34.89; T2=38.37 and T3=65.43%). In the second experiment, the objective was to evaluate the fertility of beef cows subjected to TAI using a subdose of eCG applied to the Hou Hai acupoint, and its relationship with follicular and luteal morphofunction. For this, 93 cows were subjected to the same treatments as the first experiment and the same experimental design. The results demonstrated that the application of 60 IU of eCG to the Hou Hai acupoint was effective compared to the conventional dose of 300 IU IM and the application of 60 IU to a false acupoint (IM). Cows treated with the reduced dose at the Hou Hai acupoint showed follicular and luteal morphofunctional parameters similar to those of the other groups. It is concluded that reducing the dose of eCG applied to the Hou Hai acupoint is a viable and effective alternative in TAI protocols.