272 COMPARISON OF VIABILITY BETWEEN SEXED VERSUS CONVENTIONAL BEEF SEMEN AT 37°C and 5% CO2
D. Haarmann A , M. Warshaw A , S. P. Lorton B , D. J. Kesler C and C. E. Ferguson AA Department of Agricultural Sciences, McNeese State University, Lake Charles, LA, USA;
B Reproduction Resources, Walworth, WI, USA;
C Department of Animal Sciences, University of Illinois, Urbana, IL, USA
Reproduction, Fertility and Development 25(1) 284-284 https://doi.org/10.1071/RDv25n1Ab272
Published: 4 December 2012
Abstract
This study was designed to compare the quality of sexed-sorted (X-bearing chromosome) semen and conventional semen over a 24-h period in a controlled in vitro system (37.5°C and 5% CO2). Both conventional and sexed semen (95% accurate for sexed) were collected from one Angus, Red Angus, and Hereford bull owned by CRI (Genex Cooperative, Inc., Shawano, WI, USA). The straws of sexed semen used had sperm cells sorted for X-bearing sperm (2 million sperm per straw) before cryopreservation. Semen samples were thawed in a warm water bath (37°C) and extended with BO-AB fertilization stock media. Samples were placed in the incubator for 15 min before evaluation for microscopic progressive motility, acrosomal integrity, and viability (Eosin B-Fast Green stain) at 0 (15 min after pre-incubation) 3, 6, 9, 15, and 24 h. Slides were evaluated on a heated microscope stage at 37.5°C at 400× magnification. Five replicates were performed over a 5-week period. One straw of conventional semen and one straw of sexed semen from each bull were used for each replicate. The percentage of motility, live/dead, slope of the regression line for percentage of motility, percentage of live with intact acrosome, and percentage of live for both sexed and conventional semen were analysed in SAS using the general linear models procedure (SAS Institute Inc., Cary, NC, USA) and a Tukey chi-squared post hoc test. There were no differences between bulls in each semen type; therefore, all bulls and all replicates were pooled for the final analysis. The number of live spermatozoa with an intact acrosome was higher (P < 0.05) for conventional semen compared with sexed semen at each evaluation time (Table 1). In addition, the motility remained higher (P < 0.05) for conventional semen than for sex-sorted semen throughout the experiment (Table 1). There was a difference (P < 0.05) between conventional and sexed semen in the proportion capable of fertilization (percentage of motile sperm × percentage of live sperm with an intact acrosome) from 0 h through 9 h post-thaw. The slope of the regression line for the decrease in motility plotted versus time was greater (P < 0.05) for conventional (–0.1140) than for sexed semen (–0.096); however, the slope of the regression lines for the decrease in the number of live or live with intact acrosomes was not different (P = 1.0) between conventional (–0.11; –0.11) and sexed (–0.11; –0.11) semen, respectively. These results indicate that sexed semen follows the same mortality pattern as conventional semen; however, at thawing it begins at a lower motility and viability.
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