Animal: The experiment was conducted at artificial
insemination center of a commercial swine herd in
Chonburi province, Thailand, during May and
August 2010. In total, 11 fertility-proven boars
routinely used in the farm were included in the
experiment. The boars were selected based on
previous information on their semen quality and
freezing ability. The ejaculates included in the trial
were required to have ≥70% subjective motility, ≥75%
normal morphology, ≥75% sperm viability with a
volume of ≥100 ml per ejaculate. The boars were
housed in an evaporative cooling system and each
was allocated in individual pens with space allowance
of 2.0 m2/pen. Feed was provided twice a day with a
corn-soybean-fish based commercial feed, containing
approximately 15.0% crude protein. Water was
provided ad libitum via water nipples.