An effective gilt management system involves identifying select gilts below market weight and having appropriate weights at first breeding. An important tool to achieve these is to induce first estrus with early stimulation from boars. Producers often delay inducing the first estrus until 180 to 240 days, though they are capable of reaching market weight before 170 days of age under commercial settings. By delaying pubertal estrus and breeding gilts, feed increases, barn labour and space costs increase and welfare problems may present due to increased physical size of mature sows. By 180 days of age, 80% of gilts were above market value and 23% were non-pubertal which may be a financial liability.
Growth Rate and Age at First Estrus – Impact on Managing the Gilt Pool (full article)
