Reproductive efficiency is crucial to the sustainability of any swine herd. A female’s ability to contribute to the herd earlier, longer, and more proficiently impacts her individual performance characterizing her sow lifetime productivity. Factors that impact a female’s reproductive performance vary from genetic to environmental influencers such as seasonal infertility. Age at puberty onset represents a useful tool to identify sow lifetime productivity. To determine the positive influence of age at puberty onset, physical and physiological measurements taken on a group of gilts were used to identify the potential correlation with a gilt’s age when puberty is achieved. Vulva development after postnatal day 95 and body weight on postnatal day 75 showed to be correlated to a gilt’s ability to achieve puberty earlier or later than their counterparts. While age of puberty onset can increase reproductive performance, environmental factors such as heat stress can negatively impact a female’s reproductive performance. Heat stress is a major contributing factor to seasonal infertility and is associated with decreased farrowing rates, litter performance, and wean-to-estrus intervals. Mitigating the effects of heat stress is key to increasing a female’s reproductive success. To determine how heat stress affects reproductive performance as well as how gilts adapt to stress periods, females that were either tolerant or susceptible to pre-pubertal heat stress were identified, and their response during post-pubertal heat stress periods were evaluated. A gilt’s response to pre-pubertal heat stress has a positive correlation to her response to post-pubertal heat stress. Reproductive measures of fetal weight and crown-rump length were decreased in gilts susceptible to heat stress while corpora lutea diameter was increased in heat stress tolerant gilts when exposed to heat stress during breeding.