Boars have been reported to differ in various characteristics important to productivity of AI units. These aspects include
sensitivity to seasonal infertility, ejaculate volume age interactions, optimum collection frequency, discard (trash) rate of
ejaculates, age of puberty, libido and train ability, and semen shelf life. In addition to differences among individual boars, there were
also identifiable differences among breeds, between purebreds and crossbreds, and between lines. The percentage of ejaculates
discarded varied among seasons and among breeds within season, with maternal purebred lines being the most sensitive to warmer
temperatures. These same lines were also slower to mature and produced fewer sperm per ejaculate. Breeds differed in the
sustainability of motility in stored extended semen, and in farrowing rates. Boar centers need to factor breed differences into their
decision-making processes to ensure adequate boar power and customer satisfaction.