Role of progesterone concentrations during early follicular development in beef cattle: I. Characteristics of LH secretion and oocyte quality.

Autor: Abreu FM; Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, United States; Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, OH 43210, United States., Coutinho da Silva MA; Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, OH 43210, United States. Electronic address: marco.dasilva@cvm.osu.edu., Cruppe LH; Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, United States., Mussard ML; Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, United States., Bridges GA; North Central Research and Outreach Center, University of Minnesota, Grand Rapids, MN 55744, United States., Harstine BR; Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, United States., Smith GW; Departments of Animal Science and Physiology, Michigan State University, East Lansing, MI 48824, United States., Geary TW; USDA-ARS, Fort Keogh Livestock and Range Research Laboratory, Miles City, MT 59301, United States., Day ML; Department of Animal Sciences, University of Wyoming, Laramie, WY 82071, United States.
Jazyk: angličtina
Zdroj: Animal reproduction science [Anim Reprod Sci] 2018 Sep; Vol. 196, pp. 59-68. Date of Electronic Publication: 2018 Jun 28.
DOI: 10.1016/j.anireprosci.2018.06.020
Abstrakt: Objective was to investigate the effect of different progesterone (P4) concentrations during early follicular development on luteinizing hormone (LH) secretion and oocyte characteristics in beef cows. Primiparous cows (n = 24) were estrous pre-synchronized and follicular ablation was performed (d 0) 6 days following the time of ovulation. At the time of follicular ablation, cows were assigned to either: 1) high P4 treatment - HiP4; a new CIDR was inserted on d 0 to supplement P4 from the existing corpus luteum [CL], or 2) low P4 treatment - LoP4; a previously-used CIDR and two doses of PGF 8 to 12 h apart were given on d 0. Concentrations of P4 were greater (P < 0.01) in the cows of the HiP4 than LoP4 group on d 1.5, 2.5, and 3.5. Peripheral concentrations of E2 were greater (P < 0.05) in the cows of the LoP4 than HiP4 group on d 2.5 and 3.5. Frequency of LH pulses was greater (P <  0.05) in the LoP4 than HiP4 group on d 2.5, but mean LH concentration and pulse amplitude did not differ between treatments. Number of follicles aspirated per cow, total oocytes recovered, recovery rate, percentage of oocytes graded 1 to 3, oocyte diameter, percentage BCB+ oocytes, and relative abundance of oocyte mRNA for FST did not differ (P >  0.10) between treatments. In conclusion, lower P4 concentrations during early follicular development resulted in increased LH pulse frequency and E2 concentrations, but did not affect characteristics of oocyte developmental competence.
(Copyright © 2018 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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