Effects of centrifugation and removal of seminal plasma on motility of fresh boar sperm

Extended semen from 6 boars was centrifuged and then gently resuspended (CR), had the supernatant decanted to remove residual seminal plasma and resuspended in new extender (CD), or served as non-treated controls. Measures of sperm motility were assessed immediately after centrifugation and then every 24 h until 96 h using a computer-assisted sperm analyser. Total and progressive sperm motilities were reduced (P<0.05) by 48 h in CD. Total motility was not affected in CR sperm but progressive motility was reduced (P<0.05) at 72 h. Changes with time were very similar for VSL, VAP, VCL and BCF. Control values remained relatively stable but VCL, VSL, VAP and ALH were lower within minutes of centrifugation and decanting of CD sperm. Both CR and CD treatment values for all variables were lower (P<0.05) from 3 d. These data indicate that centrifugation can negatively affect boar sperm motility and that even the small amount of residual seminal plasma in fresh-extended boar semen has a protective role. Sperm age-associated reduced motility can be countered with caffeine.