| Autor: |
Marinho, LSR, Sanches, BV, Rosa, CO, Tannura, JH, Rigo, AG, Basso, AC, Pontes, JHF, Seneda, MM |
| Předmět: |
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| Zdroj: |
Reproduction in Domestic Animals; Oct2015, Vol. 50 Issue 5, p807-811, 5p |
| Abstrakt: |
Contents The pregnancy rates obtained after the transfer of cryopreserved in vitro-produced ( IVP) embryos are usually low and/or inconsistent. The objective of this study was to evaluate the pregnancy rates of Holstein, Gyr and Holstein × Gyr cattle after the transfer of vitrified IVP embryos produced with X-sorted sperm. Seventy-two Gyr and 703 Holstein females were subjected to ovum pickup ( OPU) sessions, followed by in vitro embryo production using semen from sires of the same breeds. Embryos (1636 Holstein, 241 Gyr and 1515 Holstein × Gyr) were exposed to forskolin for 48 h prior to vitrification. The pregnancy rate achieved with Gyr dam and sire was 46.1%, which was similar (p = 0.11) to that of Holstein dam and Gyr sire (40.3%). Crossing Gyr dams with Holstein sires resulted in a pregnancy rate of 38.9% and did not differ (p = 0.58) from the pregnancy rate obtained with the cross between Holstein dams and Gyr sires. The rate obtained with Holstein dam and sire was 32.5%. The average pregnancy rate was 36.6%, and no difference was found in the proportion of female foetuses (88.8%, in average) among breeds (p > 0.05). In conclusion, transfer of cryopreserved X-sorted embryos represents an interesting choice for dairy cattle. Despite the small differences between pregnancy rates, we highlight the efficiency of this strategy for all of the racial groups studied. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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