Steve Webel United Feeds

Publish Date: June 3, 2006

Production calendars for most swine farms are based upon the reproductive cycle of sows and gilts. The key reproductive event that determines when females begin their reproductive cycles is the onset of estrus. Estrus normally occurs spontaneously in gilts and mature females that are not pregnant or lactating. Once estrous cycles have begun, they normally occur every 18 to 21 days. From a production standpoint, on any given day, it is difficult to predict or control the number of females in estrus. The ability to precisely control the onset of estrus is referred to as synchronization. Effective management and pharmacological techniques for synchronization of estrus in swine are available. However, strategies that work in prepubertal gilts are not effective in mature females and vice versa.