Study on Low Density Lipoprotein of Duck Egg Yolk as Cryoprotectants of Holstein Bulls Semen Cryopreservation

The study's goal was to evaluate the sperm qualities and fertility of Holstein bulls' cryopreserved semen in tris-extender that included various quantities of duck low density lipoproteins (DLDL) in place of whole duck egg yolk. Ejaculates with more than 70% motility and normal morphological characteristics before any supplemented. Semen was collected twice weekly from four Holstein bulls utilizing vaginal artificial means.Semen was dived to five groups after being diluted represented as, G1 contains 20% duck egg yolk, G2 contains 4%, G3 contains 6%, G4 contains 8%, and G5 contains 10% duck low density lipoprotein. A diluted sperm was inserted in 0.25 ml straws, which were then cooled and stored at 5 °C for four hours before being frozen in liquid nitrogen and stored at -196 °C. Data revealed that, G5- 10% was improvement significantly ( P≤0.05 ) in all semen characteristics than other groups.In conclusion the use low density lipoprotein of duck egg yolk at level 10% in semen extender improves sperm characteristics and fertility rate in Holstein bull semen.