Effect of programmable freezing on survival and fertility of Ram spermatozoa

Pooled ram semen samples after quality evaluation were extended in glycerolated Egg yolk Tris glucose extender @ 1x10⁶ spermatozoa per ml. Extended samples were filled in 0.25 ml straws and frozen in a programmable cell freezer @ −25°C/min up to −125°C and then stored in liquid nitrogen. Frozen straws were thawed at 50°C for 10 seconds and assessed for motility estimates by using sperm motility analyzer. It was observed that the mean progressive motility and the percentages of rapid, medium and slow categories of spermatozoa were significantly (P<0.01) reduced after equilibration. Similarly, curvilinear and average path velocities were significantly (P<0.01) decreased at the post-thaw stage. However, not much difference could be noted in the track dimensions and frequency of spermatozoa after thawing. Cervical insemination with frozen-thawed semen resulted into overall lambing rate of 23.3%. The results indicate that using EYTG extender with programmable cell freezer is a productive method for freezing ram semen.