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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Supplementation with long-acting progesterone in early diestrus in beef cattle: II. Relationships between follicle growth dynamics and luteolysis

Full text
Author(s):
Martins, T. [1] ; Pugliesi, G. [1] ; Sponchiado, M. [1] ; Cardoso, B. O. [1] ; da Silva, K. R. [1] ; Celeghini, E. C. C. [1] ; Binelli, M. [2]
Total Authors: 7
Affiliation:
[1] Univ Sao Paulo, Sch Vet Med & Anim Sci, Dept Anim Reprod, Pirassununga, SP - Brazil
[2] Univ Florida, Dept Anim Sci, Gainesville, FL 32611 - USA
Total Affiliations: 2
Document type: Journal article
Source: DOMESTIC ANIMAL ENDOCRINOLOGY; v. 68, p. 1-10, JUL 2019.
Web of Science Citations: 0
Abstract

The aims were to characterize follicular dynamics in response to supplemental progesterone (P4) and to investigate the relationships between follicular growth and onset of luteolysis in P4-treated cows, submitted or not to artificial insemination (AI). Nonsuckled beef cows detected in estrus were assigned to receive AI or to remain non-AI. Three days after ovulation (ie, D3), AI cows were injected with 150 mg of long-acting P4 (AI + injectable P4 formulation {[}iP4]; n = 22), and the non-AI cows were assigned to receive 150 mg iP4 (n = 19) or saline (control, n = 19). Between D3 and D21, growth dynamics of the dominant follicles (DFs) was monitored by ultrasonography. Plasma P4 concentrations were measured every other day from D9 to D19. Pregnancy status (ie, P: pregnant and NP: nonpregnant) was examined by ultrasound on D28 to D32. Injectable P4 formulation supplementation decreased average maximum diameter of first-wave DF (DF1). Neither day of emergence of DF2 or DF3 nor the proportion of two- or three-wave cycles were altered by supplemental P4. Daily mean diameter of DF2 and DF3 was also similar between control and iP4 groups. Consistently, daily mean diameter of DF1 in iP4-treated cows was smaller for cows that underwent luteolysis by D15 compared to a later onset. Progesterone concentrations between D9 and D19 decreased earliest in the iP4 group, latest in the control group and was intermediate for the NP-AI + iP4 group. In addition, three-wave cycles presented a delayed decrease on plasma P4 concentrations than two-wave cycles. Further analysis revealed that on two-wave cycles, P4 concentrations on D15 were lowest in the iP4 and NP-AI + iP4 animals compared to the control and P-AI + iP4 groups. Conversely, for three-wave cycles, on D15, P-AI + iP4, NP-AI + iP4, and controls had greater P4 concentrations than the iP4 group. In summary, our data indicate that impairment of first follicular growth was associated with P4-induced shortened luteal life-span (D14-D15) and that three-wave cycles after AI can be more supportive for pregnancy maintenance in P4-treated cows. We speculate that such conditions play a critical role in the embryonic ability to inhibit iP4-induced early luteolysis reported in part I of this series. (C) 2018 Elsevier Inc. All rights reserved. (AU)

FAPESP's process: 11/03226-4 - Signatures of receptivity
Grantee:Mario Binelli
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 15/26215-9 - Effect of embryo on the early luteolitic process in beef cows supplemented with P4
Grantee:Thiago Martins
Support Opportunities: Scholarships in Brazil - Doctorate