Recovery and cryopreservation of Spanish ibex epididymal spermatozoa

A Tris-citric acid-glucose (TCG) diluent containing low concentrations (6%) of egg yolk, and a TCG extender containing lactose (without egg yolk), were compared for use in the cryopreservation of Spanish ibex (Capra pyrenaica) epididymal spermatozoa. To optimize the collection of epididymal spermatozoa, two spermatozoa recovery methods were tested: i) by using small cuts in the cauda epididymides and ii) by the application of air pressure (from a syringe) inside the vas deferens. The percentage of viable spermatozoa recovered was lower (P < 0.05) with the air pressure method. No significant differences were seen in the efficacy of the two diluents as determined by percentage viability of thawed sperm, membrane integrity (as determined by the hypo-osmotic swelling test), or acrosome integrity. The use of the TCG-lactose medium strongly reduced sperm motility (P < 0.001). The sperm samples that had been diluted with TCG-6% egg yolk extender showed a greater incidence (P < 0.05) of morphological abnormalities. TCG-lactose alone, does not well preserve motility when cryopreserving Spanish ibex epididymal spermatozoa.