The use of buck and ram extenders and two packaging systems to cryopreserve aoudad (Ammotragus lervia) spermatozoa

Because the aoudad has been hunted to near extinction, cryopreservation of their semen would be useful for DNA conservation and for the possible re-establishment of captive bred animals to their former ranges. This study was conducted to investigate the effectiveness of cryopreserving aoudad spermatozoa. Semen samples from four post-pubertal animals were collected using electro-ejaculation. Microscopic analysis was performed to assess the percentages of progressively and non-progressively motile spermatozoa as well as intact acrosomes in samples prior to freezing and post-thaw. Extended samples (0.2 mL) were frozen using 2 different extenders and packaging systems and stored in LN2 Post-thaw data were arcsine-transformed and analyzed using ANOVA, 2 x 2 factorial. Samples that were processed using the ram/straw method had a significantly higher percentage (P < 0.05) of spermatozoa with intact acrosomes than did any other system. In addition, samples that were processed with the buck/pellet system had significantly greater percentages (P < 0.05) of progressive and non-progressively motile spermatozoa than the samples processed using either extender and packaged in straws. This study illustrates that some aoudad spermatozoa may be cryopreserved using the extender/processing systems developed for the domestic buck and ram.

Assessing the fertility potential of equine semen samples using the reducible dyes methylene green and resazurin

The objective of this study was to determine if spermatozoal reduction of the dyes methylene green to colorless and resazurin to pink or colorless was associated with the fertility potential of an equine semen sample. Fifty samples from 38 stallions were evaluated for the number of spermatozoa per milliliter and number of motile sperm per milliliter. Methylene green (20 micrograms/mL of semen) or resazurin (85 micrograms/mL of semen) was added to 3-mL aliquots of semen. Semen samples were identified as having low fertility potential (< 200 x 10(6) total cells/mL and < 140 x 10(6) motile cells/mL) or high fertility potential (> or = 200 x 10(6) total cells/mL and > or = 140 x 10(6) motile cells/mL). The sensitivities were 80% for the methylene green, 68% for the resazurin to pink, and 60% for the resazurin to colorless tests. The specificities were 80% for the methylene green, 79% for the resazurin to pink, and 92% for the resazurin to colorless tests. The overall accuracies were 80% for the methylene green test, 74% for the resazurin to pink test, and 76% for the resazurin to colorless tests. The methylene green and resazurin reduction tests can provide valuable information on the fertility potential of an equine semen sample.

Modified resazurin reduction test for determining the fertility potential of bovine spermatozoa

The objective of this study was to determine if reduction of the dye resazurin by bovine sperm is associated with the concentration of motile and progressively motile sperm. Metabolically active sperm reduce resazurin (blue color) to resorufin (pink color) and upon further reduction to dihydroresorufin (white color). A total of 68 semen samples from 20 Limousin bulls were collected using electroejaculation. The concentration of motile and progressively motile sperm was determined. Resazurin was added to each semen sample (8.8 microgram/mL semen), samples were then incubated at 37 degrees C for a maximum of 15 min, and visual color changes indicative of dye reduction were noted. Samples were identified as having either low fertility potential (< 200 x 10(6)/mL motile sperm and < 100 x 10(6)/mL progressively motile sperm) or high fertility potential (> or = 200 x 10(6)/mL motile sperm and > or = 100 x 10(6)/mL progressively motile sperm). Assessment of the reduction of resazurin from blue to pink (< or = 3.5 min) allowed identification of 88% of the low and 94% of the high fertility potential samples. In addition, the reduction of resazurin from blue to white (< 15 min) resulted in identification of 82% of the low and 76% of the high fertility potential samples. The modified resazurin reduction test is useful for determining the fertility potential of bovine spermatozoa.