Indução de puberdade em novilhas precoce

Abstract

INTRODUCTION: The induction of puberty through hormonal protocols is crucial in livestock farming, accelerating the reproductive development of newcomers. The use of new super-early and precocious animals increases the number of births throughout the reproductive life, increasing the productivity of the herd. OBJECTIVES: The objective of this study is to explore the effects of applying hormonal protocols in inducing puberty in heifers, evaluating their effectiveness, safety and impact on livestock productivity. METHODOLOGY: The study used a hormonal synchronization protocol for fixed-time artificial insemination (TAI) in 14 and 16 month old heifers. The protocol included insertion of intravaginal controlled release progesterone devices (CIDR®) on Day -24, followed by removal of the CIDR® and administration of estradiol cypionate (E.C.P®) 12 days later. After a 12-day rest period, the heifers were subjected to TAI on Day 0. The objective was to synchronize the heifers' estrous cycle to increase the chances of conception, providing a hormonal environment conducive to reproductive success. An integrative literature review was also carried out. RESULTS: The studies analyzed indicate that TAI protocols combined with specific hormonal interventions, such as the use of progesterone and estradiol, have been effective in inducing puberty and increasing conception and pregnancy rates in Nelore heifers and other cattle breeds. Adequate nutrition, dietary management and body condition score are crucial factors for reproductive success. Pre-synchronization and the use of intravaginal devices also positively influenced conception rates. The individualization of protocols, considering the age, weight and body condition of the heifers, is essential, and continuous evaluation of the results is necessary to refine the protocols used. CONCLUSION: The use of a hormonal protocol combining progesterone and estradiol cypionate demonstrated effectiveness in inducing puberty in Nelore heifers, promoting cyclicity and resulting in significant ovulation and pregnancy rates. The use of progesterone has been identified as more effective in inducing ovulation compared to other treatments. Furthermore, adequate nutrition and dietary management were decisive for reproductive success. Previous hormonal preparation proved to be crucial to increase the reproductive efficiency of heifers. The implementation of IATF was also highlighted as fundamental to reproductive success in precocious Nelore heifers, resulting in significant conception rates.