Fixed-time artificial insemination (IATF) in beef cattle

Abstract

This paper aims to review the methods for implementing the method reproductive IATF, associated with natural builders. More precise data on the follicular development and timing of ovulation after application of hormonal protocols can assist in determining the best time to perform the artificial insemination in fixed time. Cows should calve in good body condition to return to cicla soon after birth, the post-childbirth leads to prolonged calving interval exceeding 365 days. Playback will be considered only when all other basic energy reserves have been met, because the maintenance of life is more important, control of the estrous cycle is given by hipotólamo-pituitary axis through the release of GnRH, LH and FSH, and by hormones produced in the ovaries (estrogen and progesterone). The IATF is a reality in Brazilian livestock. Its use provides many benefits that can be said that it will change the profile of the national herd in a short period of time. Using the IATF cows have induced ovulation and IA may be marked with date and time, facilitating the work of IA. The combination of estrogen and P4 promotes the synchronization of a new follicular wave approximately 4 to 5 days after application.