In the literature, the very low pregnancy rates after artificial insemination (AI) with frozen semen in donkeys were improved in one study after re-extension of the frozen-thawed semen in autologous seminal plasma. The aims of our study were (1) to describe in vitro post-thaw parameters of donkey jackass semen after re-extension in seminal plasma (SP) or in INRA96 and (2) to compare pregnancy rates in jennies bred with frozen-thawed semen using two different AI protocols. Semen collected from two Amiata donkey stallions, known to be fertile, was frozen in INRA96 supplemented with 2% egg yolk, and 2.2% glycerol. From the same jacks, seminal plasma was filtered, and stored at -20°C. According to the in vitro analysis, the post-thaw re-extension in SP some kinematic parameters decreased more over time. Two different AI protocols were tested: inseminating deeply into the uterine horn (DHAI) with or without thawed semen re-extension in SP. Higher pregnancy rates were obtained with re-extension in SP than when AIs were performed without SP. Further studies are needed to confirm the advantage of re-extension in autologous SP of donkey frozen-thawed semen before AI in jennies.
Keywords: Artificial insemination; Donkey; Pregnancy rate, Seminal plasma, Frozen semen.
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