Evaluation of the pregnancy rate in repeat bovine females, through application of a fixed-time artificial insemination protocol with semen cool

Abstract

In the last 20 years, dairy production in cattle has increased significantly due to factors such as genetic improvement, balanced nutrition and adequate health management. However, this progress has been accompanied by reproductive problems, highlighting the decrease in the pregnancy rate, which has dropped from 60% to 42%. An important problem is the repeater cow, defined as one that, after three or more services, cannot conceive without presenting obvious reproductive pathologies. To address these challenges, biotechnological techniques have been refined, such as fixed-time artificial insemination (FTAI) using hormonal drugs to synchronize ovulation. Studies have shown that synchronization with PGF2 alpha has limitations, while IATF shows better results in general. Semen cryopreservation is common, but fresh semen, which is not subject to thermal stress, can improve sperm concentration and pregnancy rates. In Ecuador, reproductive efficiency is affected by inadequate heat detection, with 50% of cows not being detected in heat. Therefore, the use of estrus synchronization and IATF methods is recommended. This study aims to evaluate the pregnancy rate in repeater cows subjected to IATF with fresh semen and hormonal protocols. The favorable results could offer a viable alternative to improve reproductive efficiency in dairy farms.