362 STORAGE OF BOVINE SPERM FOR 20 H BETWEEN SEMEN COLLECTION AND SEXING
J. L. Anema A , J. K. Graham A , R. W. Lenz B and G. E. Seidel AA Colorado State University, Fort Collins, CO, USA;
B Sexing Technologies, Navasota, TX, USA
Reproduction, Fertility and Development 22(1) 337-338 https://doi.org/10.1071/RDv22n1Ab362
Published: 8 December 2009
Abstract
The objective of this study was to optimize bovine sperm storage for up to 20 h between semen collection and sex sorting followedby cryopreservation. Two successive ejaculates were obtained from mature dairy bulls (Holstein, n = 5; Jersey, n = 3) via artificial vagina. Treatments were then applied to the neat semen to which antibiotics were added as recommended by Certified Semen Services (Columbia, MO). Nothing further was added to the control samples until staining with Hoechst 33342 for sorting. For Treatment 1, semen was diluted 9:1 with a MOPS solution resulting in 24 mM MOPS and similarly, Treatment 2 resulted in 24 mM MOPS +2% egg yolk. A subsample of each treatment and control was sorted by flow cytometry shortly after collection, and sperm then were frozen following standard processing procedures. The other subsample was stored at 15-18°C and sorted 20 h after collection followed by cryopreservation. pH measurements were made before staining samples for sorting. Samples were evaluated post-thaw for subjective progressive and total sperm motility, by computer-assisted sperm analysis (CASA, Berkeley, CA, USA), and by flow cytometry for sperm viability using propidium iodide and SYBR-14. Treatment 1 performed better than the control (Table 1), while results for Treatment 2 were similar to the control. Second ejaculates were superior to first ejaculates. pH measurements showed that addition of MOPS kept the pH about 0.2 units higher than the control, but pH declined similarly over time in all groups. While responses for the 20 h sort were numerically lower than the 0 h sort (P > 0.1), the majority of responses were acceptable for most, but not all bulls. In conclusion, storing sperm in 24 mM MOPS was beneficial. Surprisingly, 2% egg yolk negated the beneficial effect of MOPS, possibly due to increasing osmolarity by ∼15mOsM/kg due to pH adjustment. Addition of MOPS provided better results than the control for both the 0 h and 20 h sorts.
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