John Owen - Relationship between in vitro sperm functional tests and in vivo fertility of rams following cervical artificial insemination of ewes with frozen-thawed semen.

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      Publication Details (including relevant citation   information):

      Theriogenology 69:513-522, 2008

      Abstract:

      Several procedures have been proposed to assess structural and   functional characteristics of cryopreserved ram semen but none so   far have yielded consistent relationships with in vivo fertility.   The objectives of this study were to evaluate several sperm   function tests as potential markers of in vivo ram fertility   (determined by pregnancy rate in ewes) using frozen-thawed semen.   In experiment 1, frozen-thawed straws (n=3 per ram) of semen from   three high and three low fertility rams were assessed using   fluorescent microscopy for (1) progressive motility, (2)   viability and, (3) acrosomal status. In experiment 2,   frozen-thawed straws (n=3 per ram) of semen from 18 rams of known   fertility were analysed using either computer-assisted sperm   analysis (CASA) for eight motion characteristics or flow   cytometric staining for: (1) viability and acrosomal status, (2)   plasma membrane status and capacitation-like changes, and (3)   live cells following an osmotic resistance test (ORT). In   experiment 3, platelet-activating factor (PAF) was isolated from   straws (n=2 per ram) of semen using high-pressure liquid   chromatography (HPLC) and quantified using HPLC-tandem mass   spectrometry for 18 rams. In experiment 1, no association was   found between motility, viability (% live) or acrosomal status (%   damaged, % intact and % reacted) and in vivo fertility. In   experiment 2, no correlation was found between motility (CASA),   viability (% live), acrosomal status (% live, % live intact and %   reacted), capacitation status (% capacitated, % non-capacitated),   plasma membrane stability (% dead) and % live cells following ORT   and ram in vivo fertility. In experiment 3, there was no   relationship between PAF content in spermatozoa and ram   fertility. In conclusion, we were unable to relate the in vivo   fertility of rams with in vitro functional tests of their   frozen-thawed semen and suggest that the fertility of a given   semen sample cannot easily be quantified using available in vitro   tests.

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