Factors related to reproductive development in Nellore heifers: Review

Abstract

The intensification of beef cattle production systems, aiming to increase production rates, requires the use of technologies that favor the rational exploitation of livestock. Among the animal indicators, reproductive efficiency stands out because it is closely associated with the conditions of nutrition, management and sanity, which together with the genetic pattern influence the general enjoyment of the herd. Among the Bos taurus indicus breeds used in Brazilian meat production systems, the Nellore breed occupies a prominent place, mainly due to its adaptation to the tropical climate. However, animals of this genetic group are usually sexually late than those of Bos taurus taurus bulls, even when bred in similar conditions. And within this context the age at first calving is one of the aspects that directly reflect the determination of the reproductive efficiency of the herd. Based on this assumption, the inclusion of heifers at younger ages to reproduction, providing improvements in profitability. This review aims to address some aspects related to reproductive development in Nellore heifers, such as the influence of live weight, nutrition, hormone therapy and reproductive tract morphology. According to a bibliographical survey presented in this review, it is concluded that the attainment of puberty in Nellore heifers is multifactorial and varies according to the general management of the herd and the genetic composition of the animals.