Synchronization of ovulation and fixed-time artificial insemination in beef cattle.

The main objective of the implementation of artificial insemination (AI) in cattle is to produce a sustained genetic progress in the herd. Although AI is an old reproductive biotechnology, its widespread implementation is very recent and is mainly because of the use of protocols that allows AI without oestrus detection, commonly called fixed-time artificial insemination (FTAI). The development of FTAI protocols also allowed the application of AI in larger, extensively managed herds and especially in suckled cows instead of restricting the breeding programmes to the heifers. Fixed-time AI treatments are widely used in South America, with about 3 000 000 cows inseminated in the last season in Argentina and about 8 000 000 in Brazil. The objective of this review is to present and describe the various treatments available and some of the factors that may affect pregnancy rates in beef cattle.