| Autor: |
Dovenski, Toni, Atanasov, Branko, Stojanov, Boris, Grizelj, Juraj, Mickov, Ljupčo, Nikolovski, Martin, Esmerov, Igor, Samardžija, Marko |
| Přispěvatelé: |
Rodriguez-Martinez, Heriberto, Boscos, Constantinos, Lymberopoulos, Aristotelis |
| Jazyk: |
angličtina |
| Rok vydání: |
2022 |
| Předmět: |
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| Popis: |
The aim of the study was to determinate whether exogenous progesterone (P4) before timed artificial insemination (TAI) increases the luteal regression and consequently affects fertility in heat-stressed dairy cows. Holstein cows (n = 48) during the summer season starting at day 35 ± 3 postpartum were pre-synchronized using PG-3-G protocol consisting of PGF2α (pre-PG) at random stage of the estrous cycle, 3 days later a GnRH (pre-G) injection and 10 days later submitted to an Ovsynch programme (G1–7days–PGF2α–56h–G2–16h–TAI). Cows were assigned randomly into two treatments: PRID group (n = 27) treated with P4 inserted at G1 and withdrawal at PGF2α and CON non-treated group (n = 21). Blood samples to assess P4 were collected at G1, PGF2α and at TAI. The pregnancy diagnosis was done at d30 after TAI by ultrasound. The statistical analysis has been done in Statistica 8.0 using the following tests (Levene's, t-test, One-Way Anova and Chi-square). The P4 at G1 differ (p = 0.004) between the PRID and CON groups (1.84 ± 0.99 vs. 2.97 ± 1.82 ng/ml ; mean ± SD), respectively. In contrast, the PRID group tended to have (p = 0.09) an increased P4 at PGF2α compared with the CON (4.26 ± 1.68 vs. 3.74 ± 2.39 ng/ml), respectively. In addition, the P4 at TAI differed between the treatments (p = 0.0001), with more PRID cows having a lower P4 (0.06 ± 0.03 ng/ml) compared with their herd mates (1.28 ± 2.41 ng/ml). More PRID cows were diagnosed pregnant (13/27 or 48.14%) in comparison to the CON group (8/21 or 38.08%). Treatment of cows with exogenous P4 before TAI during the heat stress increases complete luteal regression that might affect fertility. In order to confirm our findings, further studies are warranted. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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