Computer-assisted semen analysis, good sample
Computer-assisted semen analysis, good sample
Computer-assisted semen analysis, good sample

    Snapshot from a computer-assisted semen analysis (CASA) video of a good ("green") semen sample from a bull. Progressively motile spermatozoa are coded green; static spermatozoa are coded red. Note the frequent green spermatozoa in this sample.

Courtesy of Dr. Jonathan Statham.