| Autor: |
Barletta RV; Department of Dairy Science, University of Wisconsin, Madison 53706; Department of Animal Science, University of São Paulo, SP 13418-900, Brazil., Carvalho PD; Department of Dairy Science, University of Wisconsin, Madison 53706., Santos VG; Department of Dairy Science, University of Wisconsin, Madison 53706., Melo LF; Department of Dairy Science, University of Wisconsin, Madison 53706., Consentini CE; Department of Dairy Science, University of Wisconsin, Madison 53706., Netto AS; Department of Animal Science, University of São Paulo, SP 13418-900, Brazil., Fricke PM; Department of Dairy Science, University of Wisconsin, Madison 53706. Electronic address: pmfricke@wisc.edu. |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of dairy science [J Dairy Sci] 2018 Feb; Vol. 101 (2), pp. 1730-1736. Date of Electronic Publication: 2017 Dec 08. |
| DOI: |
10.3168/jds.2017-13628 |
| Abstrakt: |
Our objective was to evaluate the effect of a second PGF 2α treatment (25 mg of dinoprost) or a double dose of PGF 2α (50 mg of dinoprost) during a Resynch protocol on luteal regression and pregnancies per artificial insemination (P/AI) in lactating dairy cows. Lactating Holstein cows (n = 1,100) were randomly assigned at a nonpregnancy diagnosis to receive (1) Ovsynch (control: 100 µg of GnRH; 7 d, 25 mg of PGF 2α ; 56 h, 100 µg of GnRH), (2) Ovsynch with a second PGF 2α treatment (GPPG: 100 µg of GnRH; 7 d, 25 mg of PGF 2α ; 24 h, 25 mg of PGF 2α ; 32 h, 100 µg of GnRH), or (3) Ovsynch with a double dose of PGF 2α (GDDP: 100 µg of GnRH; 7 d, 50 mg of PGF 2α ; 56 h, 100 µg of GnRH). All cows received timed artificial insemination (TAI) approximately 16 h after the second GnRH treatment (G2). Pregnancy diagnosis was performed by transrectal palpation 39 ± 3 d after TAI, and pregnancy status was reconfirmed 66 d after TAI. Blood samples collected from a subset of cows in each treatment at the first PGF 2α treatment (n = 394) and at G2 (n = 367) were assayed for progesterone (P4). Data were analyzed by logistic regression using the GLIMMIX procedure of SAS (SAS Institute Inc., Cary, NC). At 39 d after TAI, GPPG cows tended to have more P/AI than control cows [35% (137/387) vs. 31% (107/349)], whereas P/AI for GDDP cows [32% (118/364)] did not differ from that for control cows. Pregnancy loss from 38 to 66 d did not differ among treatments and was 8% (30/362). The percentage of cows with complete luteal regression (P4 <0.4 ng/mL at G2) tended to differ among treatments and was greater for GPPG cows than for GDDP and control cows (94% vs. 88% vs. 88%, respectively). Overall, cows with P4 <1 ng/mL at the first PGF 2α treatment had fewer P/AI than cows with P4 ≥1 ng/mL (27% vs. 38%), whereas cows with P4 ≥0.4 ng/mL at G2 had fewer P/AI than cows with P4 <0.4 ng/mL (15% vs. 38%). We conclude that adding a second PGF 2α treatment 24 h after the first within a Resynch protocol tended to increase the proportion of cows undergoing complete luteal regression and P/AI, whereas treatment with a double dose of PGF 2α at a single time did not.
(Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.) |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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