Comparison of commercial Triladyl extender with a tris-fructose-egg-yolk extender on the quality of frozen semen and pregnancy rate after transcervical AI in Bangladeshi indigenous sheep (Ovis aries)

• We study compare the effects of commercial Triladyl® and tris fructose egg yolk extenders on frozen ram semen quality.
• We study compare the effects of extenders on PR following transcervial AI in ewes.
• Commercial extender is better for frozen sperm quality compare with locally manufactured extender.
• Pregnancy rate is similar for commercial and locally manufactured extender.

The objective of this study was to compare the effects of commercial and locally manufactured tris-fructose-egg-yolk semen extenders on the quality of frozen semen and pregnancy rates (PR) after AI of Bangladeshi indigenous sheep. Semen was collected weekly by artificial vagina (AV) from 6 mature indigenous rams (Ovis aries). Each semen sample was diluted with commercial (Triladyl®) and locally manufactured (tris, fructose, egg-yolk, 7% glycerol) extenders, to a final concentration of 200, 400 and 600 × 106 sperm/mL. Semen samples were frozen in 0.25 mL mini-straws in liquid nitrogen (LN) vapor for 6 min and then stored in LN. Post-thawing motility, viability, functional integrity and normal morphology were evaluated on Days 1, 5 and 30 of storage. Post-thaw sperm quality parameters were better (p < 0.001) in Triladyl than in the locally manufactured extender; and quality parameters were also higher for a pre-freezing concentration of 400 × 106 sperm/mL (p < 0.001) than for other concentrations, regardless of extender. Storage time did not affect semen quality parameters (p > 0.001). Indigenous ewes (n = 46) were inseminated transcervically using semen from both extenders at a sperm concentration of 400 × 106/mL. There was no difference in the pregnancy rates between sperm frozen in Triladyl compared with the locally manufactured extender (p > 0.70). In conclusion, whilst post-thaw sperm quality was better in semen frozen in Triladyl, this did not result in any significant benefit compared with the locally-prepared extender on PR after TCAI in ewes.