Comparing the effect of estradiol benzoate and 17 beta-estradiol plus progesterone on follicular turnover and development, and pregnancy outcomes in a timed artificial insemination protocol

Author(s)

Rocha, Cecilia Constantino ; Martins, Thiago ; Mello, Barbara Piffero ; de Mello, Gabriela Dalmaso ; Motta, Igor Garcia ; Lemes, Kleber Menegon ; Binelli, Mario ; Madureira, Ed Hoffmann ; Pugliesi, Guilherme

• Document type: Journal article
• Source: Theriogenology; v. 192, p. 8-pg., 2022-10-15.

Abstract

The objective of this study was to compare the efficiency of estradiol benzoate (EB) and 17b-estradiol (E2) associated with progesterone (P4) in a fixed-time artificial insemination (FTAI) protocol. We hypothesized that E2thornP4 induces an earlier emergence of a new follicular wave (NFW), improving preovulatory follicle diameter and pregnancy rates to FTAI (P/FTAI). In Exp.1, on Day 0 (D0), all Bos indicus cows (n = 12/group) received an intravaginal P4 device and a dose of PGF2 alpha analogue. On D0, females were randomly assigned to receive EB or E2thornP4. On D8.5, P4 intravaginal devices were removed and a dose of PGF2 alpha and EB were administered in all females followed by fixed-timed AI on D10. Between D0 and D10, the dominant follicular growth was determined by ovary ultrasonography exams. On D8.5 and D10 the percentage of color power-Doppler signals in the dominant follicular wall was evaluated. In Exp. 2, 467 females (2-year-old nulliparous [n = 76], primiparous [n = 92] and pluriparous [n = 299]) were subjected to the similar FTAI and assigned to be treated with EB (n = 243) or E2thornP4 (n = 224). Pregnancy diagnosis was performed 30 days after FTAI by ultrasonography. The day to emergence of NFW was similar between treatments (EB: 3.7 +/- 0.37 vs. E2thornP4: 3.3 +/- 0.3, P = 0.76). Females treated with E2thornP4 presented greater (P = 0.06) follicular growth between the emergence and D9 (1.18 +/- 0.07) than those treated with EB (0.97 +/- 0.08). There was also a positive effect (P < 0.05) of E2thornP4 on diameter of the dominant follicle on D9 (13.0 +/- 0.6 vs. 10.9 +/- 0.55) and blood perfusion of the follicle wall on D8.5 (49 vs. 40%). There was a treatment by parity category interaction effect on P/FTAI (P < 0.05). Treatment with E2thornP4 was advantageous to P/FTAI of primiparous cows (E2thornP4: 58% and EB: 30%). However, for nulliparous and pluriparous cows, P/FTAI was similar between treatments (similar to 50%). In conclusion, in a E2/P4-based protocol for FTAI, E2thornP4 is as efficient as EB in inducing new follicular emergence within a similar day range, but it results similar or greater P/FTAI. (AU)

• FAPESP's process: 17/13994-5 - Study of transcriptomic profile in immune cells of peripheral blood during early pregnancy in beef heifers
• Grantee: Cecilia Constantino Rocha
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 15/10606-9 - Innovations in the early pregnancy diagnosis in cattle
• Grantee: Guilherme Pugliesi
• Support Opportunities: Research Grants - Young Investigators Grants