EVALUATION AND COMPARISON OF PREGNANCY RATE IN MESTROSE COWS SUBJECTED TO NATURAL MILLING AND FIXED-TIME ARTIFICIAL INSEMINATION IN THE MUNICIPALITY OF ESPIGÃO D’OESTE – RO

Abstract

Brazil has the largest commercial herd in the world, consisting mainly of zebu breeds. in these animals, the main form of reproduction still used in the peculiarity is natural assembly, however with the growth in market demand to obtain excellent animals, it is essential to seek effective means to meet the demand. fixed-time artificial insemination (iatf) is a reproductive biotechnology that seeks genetic improvement through the use of hormonal protocols and artificial insemination. therefore, the purpose of the study is to evaluate the efficiency and prescription of using tai and natural assembly by comparing the results obtained in both. the study was carried out in the municipality of espigão d’oeste-ro, with 160 mixed-race vacancies, with an average age of 5 years, with a body score of 3 (scale from 1 to 5). these matrices were divided into 2 batches, with the 1st batch having 80 multiple vacancies, with natural mounting being the reproductive means used, with four nelore pure origin bulls, for 30 days. the 2nd batch had 80 multiparous places, which were submitted to the iatf, complying with the hormonal protocol (d0 and d8) and insemination (d10). the result obtained was that with the iatf, a higher percentage of pregnancy rate was obtained (87.5%), whereas with the natural assembly, a lower pregnancy rate was obtained, 58.75%. therefore, it is noted that despite the natural mountain being the most used and considered more economical, the iatf provided better reproductive rates.