Reproductive responses of Charolais cattle under tropical conditions.

Artificial insemination (AI) is a tool used for the genetic improvement of livestock in the tropics. Fixed-time artificial insemination (FTAI) is an assisted reproduction technique that has had great development in recent years. Oestrus synchronization protocols are alternatives for ovulation and fertilization control. Reproductive efficiency is an important aspect in cattle production, which has a cost-benefit impact on cattle production. The use of these alternatives increases the number of cows inseminated in a short period of time. The use of IATF protocols based on previous studies show that the pregnancy rate is 40-50%. To consider IATF successful, the highest number of pregnant cows and live calf births should be obtained. Other benefits of IATF are the reduction of insemination time, shortening the postpartum period and improving the results of cows with calves at foot. The most important limiting factor of these protocols is the reduction of fertility after artificially or hormonally inducing estrus.