The present study was carried out on of 198 frozen semen straws taken from 22 buffalo bulls (< 5, 5-10 & >I0 years old) at three storage periods (1, 2 & 3 years) with three repetitions. Results revealed more improvement in the sperm viability and fertilizing capacity for bulls aged 5 - 10 years when compared to other age groups. Although there was a non-significant improvement in the quality tests of spermatozoa a non-significant decrease appeared in the conception rate of the buffalo frozen semen stored for three years o r m ore. It was concluded that buffalo bulls aged up to 10 years have more efficiency in artificial insemination purposes based on their high semen quality and fertilizing capacity; storage of the frozen semen seems to depend more on the change in systems of freezing, thawing and handling than the length of the storage period |