Adding a second prostaglandin F2α treatment to but not reducing the duration of a PRID-Synch protocol increases fertility after resynchronization of ovulation in lactating Holstein cows
| Autor: | V.G. Santos, A. Valenza, P.M. Crump, Paul M. Fricke, Cristiano Cardoso Maia, P.D. Carvalho, B. Carneiro |
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| Rok vydání: | 2016 |
| Předmět: |
Ovulation
0301 basic medicine medicine.medical_specialty medicine.medical_treatment media_common.quotation_subject Prostaglandin Fertility Luteal phase Dinoprost Gonadotropin-Releasing Hormone Andrology 03 medical and health sciences chemistry.chemical_compound Internal medicine Genetics medicine Animals Lactation Insemination Artificial Progesterone media_common Pregnancy business.industry Artificial insemination 0402 animal and dairy science 04 agricultural and veterinary sciences Abortion Veterinary medicine.disease 040201 dairy & animal science 030104 developmental biology Endocrinology chemistry Cattle Female Animal Science and Zoology Estrus Synchronization business Food Science |
| Zdroj: | Journal of Dairy Science. 99:3869-3879 |
| ISSN: | 0022-0302 |
| DOI: | 10.3168/jds.2015-10557 |
| Popis: | Our objective was to evaluate the effect of a second PGF 2α treatment and duration of an Ovsynch protocol that included a progesterone-releasing intravaginal device (PRID) on progesterone (P4) concentrations and pregnancies per artificial insemination (P/AI) after resynchronization of ovulation and timed artificial insemination (TAI). Lactating Holstein cows (n=821) were assigned randomly at a nonpregnancy diagnosis (d 0) to 3 resynchronization protocols: (1) GnRH, d 0; PGF 2α , d 7; GnRH, d 9.5 (7D1PGF); (2) GnRH, d 0; PGF 2α , d 7; PGF 2α , d 8; GnRH, d 9.5); (7D2PGF); or (3) GnRH, d 2; PGF 2α , d 7; PGF 2α , d 8; GnRH, d 9.5 (5D2PGF). All cows received a PRID at the first GnRH treatment of the resynchronization protocol, which was removed at the first PGF 2α treatment, and all cows received TAI approximately 16h after the second GnRH treatment. Blood samples were collected from a subgroup of cows at each treatment of the resynchronization protocols. At 32 d after TAI, cows receiving a second PGF 2α treatment (7D2PGF + 5D2PGF cows) had more P/AI (42.6 vs. 35.7%) than cows receiving a single PGF 2α treatment (7D1PGF cows). For cows treated with a second PGF 2α treatment, decreasing the duration of the protocol did not increase P/AI (41.4 vs. 43.8% for 7D2PGF vs. 5D2PGF cows). At 60 d after TAI, P/AI did not differ between cows treated with the 1 PGF 2α (7D1PGF cows) or 2 PGF 2α (7D2PGF + 5D1PGF cows) treatments (32.5 vs. 37.9%, respectively). In addition, reducing the duration of the protocol did not increase P/AI at 60 d after TAI (37.8 vs. 38.5% for 7D2PGF vs. 5D2PGF cows). Pregnancy loss from 32 to 60 d after TAI was not affected by the number of PGF 2α treatments (8.5 vs. 10.6%, for 7D1PGF vs. 7D2PGF + 5D2PGF cows) or the duration of the protocol (9.1 vs. 12.1%, for 7D2PGF vs. 5D2PGF cows). The percentage of cows with incomplete luteal regression at the second GnRH treatment tended to differ among treatments and was lowest for 7D2PGF cows, intermediate for 5D2PGF cows, and greatest for 7D1PGF cows (1.9 vs. 6.9 vs. 11.0%, respectively). In conclusion, addition of a second PGF 2α treatment tended to decrease the percentage of cows with incomplete luteal regression and increased P/AI 32 d after AI, whereas decreasing the duration of the Ovsynch protocol did not increase P/AI. |
| Databáze: | OpenAIRE |
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