Abstract

The predictability of semen quality of mature sires from measurements at an early age is not well established. The aim of the present study was to determine age-dependent changes in the quality of bull semen for artificial insemination (AI). Semen was collected and frozen from each of six Swedish Red and White (SRB) dairy AI buns when they were 1 and 4 years old. Three batches were randomly selected from each bull and age group. From each batch, semen was analysed immediately after thawing [post-thaw (PT), control] as well as after washing/resuspension (W) and after a swim-up procedure (SU). The analyses comprised subjective and computerized (computer-aided sperm analysis, CASA) measurements of motility as well as sperm concentration, morphology and membrane integrity. When semen was analysed, PT, overall sperm motility (CASA), concentration of motile spermatozoa and membrane integrity improved when sires were older. After SU, there was a similar improvement in membrane integrity and concentration of motile spermatozoa, but linear motility decreased. No significant differences between ages were recorded after W-treatment. The above findings indicate that SU is not only superior to W-treatment in differentiating semen quality among bulls but also reveals age-dependent changes. Improved motility and membrane integrity suggest increased viability of spermatozoa at 4 years of age in the SRB sires examined here

Published in

International Journal of Andrology
2004, volume: 27, number: 3, pages: 166-171
Publisher: BLACKWELL PUBLISHING LTD

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