Brazilian Nelore cattle: a melting pot unfolded by molecular genetics

Abstract

ABStrACt. The aim of the present article was to study the population structure and genetic diversity of Nelore cattle and genetic relationships between Nelore and different taurine and zebu breeds raised in Brazil. DNA polymorphism analysis was carried out with 1976 animals of 16 zebu, taurine and synthetic breeds raised in Brazil. A higher genetic differentiation was observed in taurine than in zebu cattle. Gene flow was intense between the different zebu populations. Genetic affinity analysis within the most conspicuous Brazilian zebu beef cattle, the Nelore, was carried out in a group of 615 animals from 15 representative herds. This analysis revealed at least two major Nelore subtypes, named after some genotype-phenotype associations such as the "thrifty type" and the "demanding type". This study provides molecular genetic evidence that, despite selection based on the phenotype, gene flow and gene segregation still play a major role in maintaining genetic variability within the Nelore and zebu population as a whole in Brazil.

Genetic diversity and differentiation of exotic and American commercial cattle breeds raised in Brazil

“…Nonetheless, large-scaled commercial production systems were established only after the importation of zebuine breeds from India in the late 19th and 20th centuries (Cervini et al, 2006). Adapted to the tropical ecological settings found in Brazil, zebuine cattle rapidly became prominent in most herds and contributed to the development of new American breeds such as Nelore, Tabapuã, Indubrazil, and Girolando (Dani et al, 2008). Other conspicuous commercial breeds raised in Brazil, such as Brahman and Senepol, were also formed during the last century, although in other countries of the American continent (Novoa and Usaquén, 2010).…”

“…These animals resulted, in the large part, from absorbing crossbreeding between zebuine bulls imported from different regions of India and local taurine dams (Mariante et al, 1999). Furthermore, Brazilian Creole cattle also contributed to the formation of some American derivatives of zebuine breeds (such as Tabapuã) (Mariante et al, 1999;Dani et al, 2008). It has been shown that Latin American Creole breeds may carry either European-or Africanoriginated taurine DNA (Lirón et al, 2006;Ginja et al, 2010).…”

“…Currently, the majority of the herd comprises exotic breeds of both taurine and zebuine origins and their American derivatives that were imported during the last 100 years (Cervini et al, 2006). The improvement of cattle in Brazil has frequently involved crossings between zebu and taurine cattle as well as between different zebu breeds (Dani et al, 2008). This occurred due to the better adaption of zebuine breeds to tropical ecological settings than taurine breeds.…”

“…Recent studies evaluated the genetic structure and diversity of locally adapted Creole cattle and some commercial breeds in Brazil and other Latin American countries (Cervini et al, 2006;Lirón et al, 2006;Egito et al, 2007;Dani et al, 2008;Delgado et al, 2012). The data reported indicate that variable patterns of breed admixture have occurred since colonial times that have shaped the current genetic status of the local breeds.…”

“…Especially, data related to conspicuous breeds developed in America during the 20th century, e.g., Nelore, Brahma, and Senepol, are scarce. In addition, strong directional selection has shaped commercial bovine populations in Brazil for decades, possibly leading to significant reductions in the effective population size (Egito et al, 2007;Dani et al, 2008).…”