Fig. 2

Effect of REAC treatment on the kinetic parameters of stallion spermatozoa during 72 h. of storage at 4 °C. Values determined at the different time points are expressed as mean ± S.E. A total of 16 ejaculates collected from eight stallions of different breeds (1: Thoroughbred; 2, 3, 4, 6: Arabian; 5, 7, 8: Warmblood) were used. Different letters indicate a statistical difference among values recorded at the different time points within the same experimental group (General Linear Model): p > 0.01. Upper case letters: REAC group; lower case letters: control group. PM: percentage of progressive motile spermatozoa; Rapid: percentage of rapid spermatozoa; VAP: average path velocity (mm/s; the average velocity of the smoothed cell path); VCL: curvilinear velocity (mm/s; the average velocity measured over the actual point to point track followed by the cell); VSL: straight-line velocity (mm/s; the average velocity measured in a straight line from the beginning to the end of the track); LIN: linearity index (%; the average value of the ratio VSL/VCL); STR: straightness index (%; the average value of the ratio VSL/VAP); ALH: amplitude of lateral head displacement (mm; the mean width of the head oscillation as the sperm swim); BCF: beat cross-frequency (Hz; the frequency of sperm head crossing the average path in either direction); WOB: wobble (VAP/VCL × 100, %; a measure of the oscillation of the actual trajectory about its spatial average path)