Effects of Proportion of Egg Yolk and Preservation Time on Chilled Semen from Indigenous Rams

Abstract

The study was set out to determine the effects of different percentages of egg yolk on quality of chilled semen in Indigenous Rams. Different percentages of egg yolk were used to preserve semen from indigenous rams in Tris based extender at 4°C. Nine 2 to 3 years old rams, weighing 21.5±1.2 kg, body condition score 3.9±0.1 with scrotal circumference of 22.4 ±0.4 cm were selected for collection of semen once a week using artificial vagina. Each ejaculate was divided into four portions, and extended with Tris based diluents containing 5, 10, 15, and 20% egg yolk and kept chilled at 4 to 5°C for up to 48h. Motility, viability, functional integrity and morphology were evaluated before and 24h and 48h of preservation. The results showed significantly (p<0.05) better motility, viability and functional integrity with 10% egg yolk compared to other concentrations of egg yolk during preservation. However, the proportion of egg yolk did not affect spermatozoa quality before preservation and normal morphology in any time during preservation. Time of preservation decreased (p<0.01) the rate of motility, viability, functional integrity, and normal morphology of spermatozoa. Positive correlation coefficient observed between spermatozoa motility, viability, and functional integrity. Functional integrity of spermatozoa positively correlated to morphologically normal spermatozoa. It is concluded that 10% egg yolk in Ttris based diluents may be best for chilled Indigenous ram semen.