Management Practices to Reduce the Impact of Seasonal Infertility on Sow Herd Productivity

During summer and early fall, many sow farms experience a variety of reproductive problems, such as, anestrus, extended weaning-to-estrus intervals, poor conception rates, higher embryo mortality rates and low farrowing rates. This phenomenon is commonly referred to as “seasonal infertility” and can also be present in boar studs, where the result is lower semen output and lower semen quality. Most researchers have attributed this seasonal infertility to heat stress and the fact that pigs are inherently seasonal breeders. Before pigs were domesticated, both sows and boars were seasonal breeders. In North America, pigs entered an anestrous season in the summer and early fall, which avoided the birthing of offspring in winter, a time when survival would not be optimal. The primary goal of every operation must be to incorporate environmental strategies to reduce heat stress. Additionally, non-thermal interventions may also be incorporated into management strategies on a case by case basis (Table 1.) Most operations use many, but perhaps not all of the suggested methods to reduce the impact of seasonal infertility discussed in the proceeding text. The objectives here are to provide producers with the necessary background information to explore current and potential interventions that are not presently being conducted and develop an annual action list to reduce the seasonal effects on fertility.