Role of progesterone concentrations during early follicular development in beef cattle: I. Characteristics of LH secretion and oocyte quality
| Autor: | M.A. Coutinho da Silva, George W. Smith, F. M. Abreu, G.A. Bridges, M.L. Mussard, M.L. Day, Thomas W. Geary, L. H. Cruppe, B.R. Harstine |
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| Rok vydání: | 2018 |
| Předmět: |
Ovulation
endocrine system media_common.quotation_subject Biology Beef cattle Andrology 03 medical and health sciences 0302 clinical medicine Endocrinology Food Animals Ovarian Follicle Corpus Luteum Follicular phase medicine Animals Progesterone media_common Estrous cycle 030219 obstetrics & reproductive medicine Lh secretion 0402 animal and dairy science 04 agricultural and veterinary sciences General Medicine Luteinizing Hormone Oocyte 040201 dairy & animal science medicine.anatomical_structure Oocytes Animal Science and Zoology Cattle Female Progestins Luteinizing hormone Estrus Synchronization Corpus luteum |
| Zdroj: | Animal reproduction science. 196 |
| ISSN: | 1873-2232 |
| Popis: | 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 (P0.01) in the cows of the HiP4 than LoP4 group on d 1.5, 2.5, and 3.5. Peripheral concentrations of E2 were greater (P0.05) 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. |
| Databáze: | OpenAIRE |
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