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Spermatozoa Statistics in StallionsBy Kentucky Equine Research Staff · March 17, 2015

At 70 to 80 microns, stallion spermatozoa measure only half the length of mouse spermatozoa, but size isn’t everything. Sometimes quantity counts!

Spermatogenesis, the production of mature sperm cells, takes about 57 days in stallions, but this continuous process yields billions of sperm during each breeding season.

In spite of the huge number of viable sperm produced, conditions within the mare’s reproductive tract result in the death of most sperm before they reach the ovum. On average, only about 0.0006% of sperm survive the trip to the mare’s oviduct.