K.C. Lehloenya

The effect of breed on the survivability and motility rate of

This study evaluated the effect of breed on the survivability and motility rate of cryopreserved cock semen. Semen from three cock breeds; White Leghorn (WL), Ovambo (OV) and Potchefstroom Koekoek (PK) was collected by means of the abdominal massage technique. Following semen collection, sperm were analyzed for motility and survivability with the use of contrast light BHTU microscope (20 x magnification). The semen was diluted (1 : 2 v/v) with egg yolk citrate (EYC) (extender A) and thereafter with extender B (EYC + 5% DMSO). The equilibration after each dilution was 2 h at 5 °C. The diluted samples were evaluated for sperm concentration, motility, survivability and pH. The samples were then loaded into straws and cooled in programmable freezer from 5 °C to -20 °C at the rate of 1 °C/minute. Semen straws were then exposed to liquid nitrogen vapour (-80 °C) for five minutes, plunged directly into liquid nitrogen (-196 °C) and stored for a week or more. Frozen straws were thawed at 5 °C and evaluated at 0, 30, 60 and 90 min post-thaw. From the results there was no significant effect of breed on the survival and motility of fresh-diluted and frozen-thawed semen at 30 and 90 min post-thaw in all breeds. The sperm survivability of the PK breed was significantly higher than that of the WL breed. However, there was no sperm survivability difference between PK and OV breed immediately after thawing. The cryopreservation and thawing processes affected the survivability and motility of sperm of all poultry breeds negatively.