Puberty is attained more gradually in boars than in gilts. By 5 months of age, most boars can ejaculate sufficient numbers of sperm for fertile mating. By 8 months of age, adequate sperm numbers are produced for use in a breeding program. Mature adult sperm numbers are achieved by 18 months of age.
Boars raised in groups attain puberty earlier, and have more aggressive libidos.
Exposure of prepuberal boars to sows or gilts improves postpuberal sexual behavior. Boar libido is probably heritable. The mating behavior of boars consists of grunting, nuzzling, and chomping behaviors with copious salivation when in contact with the sow. This will cause initiation of the lordosis reflex in the sow. Multiple false mounts may occur before copulation.