Research Progress of Timed Artificial Insemination in Sow Reproduction

The demand for intensive, large-scale and effective breeding pattern is growing in pig breeding industry. Traditional estrus detection and insemination methods are time-consuming and expensive while more likely to be delayed in sow reproduction. Timed artificial insemination(TAI)is an innovative technology combining the artificial insemination and estrus synchronization. It helps to regulate reproductive hormones secretion and the follicular development in sows by adding exogenous synthetic hormones to make sows show estrus, ovulate and be inseminated during a given time. Moreover, this technology contributes to reducing the dependence on estrus detection, production loss caused by recessive estrus and crossing infection, and helps increase sows'reproduction frequency per year and reproductive rate as well as facilitate epidemic prevention. However, TAI has been introduced into China for a short time, and it still has many problems, including unstable effects and insignificant increase in the number of embryos, which need further researches and solutions. This article summarizes the regulation law of reproductive hormones in sows as well as the ways to develop TAI for sows at different stages of production, and analyzes the application effects of various hormones and key factors affecting hormone effects to provide a reference for optimizing TAI procedure and improving reproductive management level for sows.