High-throughput characterisation of bull semen motility using differential dynamic microscopy

We report a high-throughput technique for characterising the motility of spermatozoa using differential dynamic microscopy. A large field of view movie (~ 10mm 2 ) records thousands of cells (e.g. ≈ 5000 cells even at a low cell density of 20 × 10 6 cells/ml) at once and yields averaged measurements of the mean ( υ ) and standard deviation ( σ ) of the swimming speed, a head oscillation amplitude ( A 0 ) and frequency ( f 0 ), and the fraction of motile spermatozoa ( α ). Interestingly, the measurement of α relies on the swimming spermatozoa enhancing the motion of the non-swimming population. We demonstrate the ease and rapidity of our method by performing on-farm characterisation of bull spermatozoa motility, and validate the technique by comparing laboratory measurements with tracking. Our results confirm the long-standing theoretical prediction that for swimming spermatozoa.