Photographer Leonhard Foeger documented the process as workers collected semen from breeding bulls at an artificial insemination centre in Hohenzell, Upper Austria. The bulls at the centre mount either an artificial cow or another bull to ejaculate so that their semen can be collected. The quality of the sperm is then checked, and the semen is diluted and preserved in tanks full of liquid nitrogen before being shipped out to clients. The breeding centre exports cattle semen to more than 52 countries worldwide and last year it sold approximately 800,000 samples. Portions of semen from bulls belonging to the Simmental breed cost between 6 and 15 euros. One bull at the centre, Wille, has produced 5 million euros worth of semen over the course of his lifetime.