The boar is obviously an essential part of any swine operation. There is a lot of labour involved with the use of a boar in an AI system, so the question arises: is it worth it? We know that boars can stimulate puberty, heat detection, and return to estrus, but can it actually increase fertility? Boars release pheromones (specifically, androstenol and androstenone), which are smelled by the female and help to invoke a standing response. Boar stimulation will also increase the release of LH (Luteinizing Hormone) in the female, which will lead to follicle development, production of steroids, and ovulation. Young boars are not effective in reducing the age to puberty in gilts. Wean to service intervals can be impacted by boar exposure and even exposure to estrus sows. Some causes of reduced fertility (such as season or parity) can be relieved to some degree by controlled boar exposure. Research shows that 48% of females will stand without boar exposure, but with all types of stimulus this number can be bumped up to 97%. Boars may help AI success by inducing uterine contractions by the sow by inducing an oxytocin release. Boar exposure at time of mating can also serve as added insurance against excessive leakage at insemination.