Computer-assisted semen analysis and its utility for profiling boar semen samples

Achieving and maintaining a successful swine AI program depends on a number of factors, including accurate semen evaluation, typically sperm motility, morphology and concentration. Computer-Assisted Semen Analysis or CASA (i.e., image analysis with a phase-contrast microscope and computer measurements of motion parameters) objectively evaluates sperm motion characteristics, morphology and concentration. A total of 3077 semen collections were evaluated with CASA (on the day of collection), and a semen dose subset was used for single-sire AI of 6266 females over 6 months. Fertility data from these inseminations were fitted with models including farm/stud, line, boar, parity, mating week, semen age at mating and boar age at mating. The residuals from these models showed no correlation for any CASA semen unique motion parameter, which could be due to the level of sperm concentration, the number of inseminations per estrus, and the low number of females mated per boar. Future studies to expand CASA/fertility analysis need to address these constraints and may include analysis of extended boar semen after storage for 1 week.