Bos indicus or Bos taurus mitochondrial DNA - comparison of productive and reproductive breeding values in a Guzerat dairy herd

Abstract

ABSTRACT. The observation of bovine mitochondrial DNA (mtDNA) polymorphisms allows the separation of American zebu cattle, according to its maternal lineage ancestry, into two groups: one with Bos indicus mtDNA and other with Bos taurus mtDNA. The aim of the present study was to determine the productive and reproductive differences between these two groups, in a Guzerat dairy herd. The genotyping of a sample of 56 animals allowed the categorization of most of the 3835 animals in the pedigree file. The production file included 3528 calving and 3198 lactation records from 729 cows, born during the years 1947 to 2007. The traits considered were: lactation milk yield (LMY); days in milk (DIM); age at first calving (AFC), and calving interval (CI). Heritabilities and breeding values were estimated using an animal model. The regression of the average breeding values per year of birth indicated the genetic trends of the herd. The heritability coefficients estimated for LMY, DIM, AFC, and CI were 0.42, 0.43, 0.20, and 0.10, Bos indicus or Bos taurus mitochondrial DNA -Guzerat respectively. The genetic trends were similar for both groups, pointing to an improvement in the productive and a worsening in the reproductive traits. The two groups differed significantly regarding the average estimated breeding values for LMY, DIM and AFC, in the starting period, until 1970, but no differences were observed in the more recent years, after 1970. The segregation between the groups existed in the starting period, probably because the Bos taurus contributions to the herd had occurred more recently at that moment. The conclusion is that mtDNA has no significant effect on these traits.

Meta-Analysis of Mitochondrial DNA Reveals Several Population Bottlenecks during Worldwide Migrations of Cattle

“…One of the T4-specific substitutions leads to an L380M mutation in the cytochrome b gene and the G1324A substitution in T1c1a1 causes a mutated rRNA. However, no differences have been found in production and reproduction traits between Brazilian Guzerat zebus carrying taurine mtDNA and those carrying indicine mtDNA [43]. Nonetheless, there is no a priori reason why mtDNA-encoded gene products cannot be involved in selection and contribute to traits relevant for adaptation or production, thus leading to geographic differentiation of mtDNA.…”

Interrogation of modern and ancient genomes reveals the complex domestic history of cattle

“…More recent Indian zebu genetic influence in New World populations is supported by several lines of evidence including mtDNA (Magee et al, 2002;Paneto et al, 2008), Y chromosome microsatellites (Giovambattista et al, 2000), and autosomal STR and SNP genetic markers (Liron et al, 2006;Egito et al, 2007;Achilli et al, 2009;McTavish et al, 2013). Interestingly, McTavish et al (2013) suggest that the zebu ancestry observed in New World cattle may have originated, in part, from the founding Iberian cattle of the Americas; however, the lack of zebu ancestry in Iberian cattle has led Decker and colleagues (2014) to refute this and propose that zebu introgression in the Americas occurred after the arrival of Iberian cattle in the New World.…”

On the origin of cattle: How aurochs became cattle and colonized the world

“…The percentage of animals with zebu mtDNA varies in Brazil from 37% in the Gir breed to 43% in the Nelore 61 and 69% in the Guzerat breeds. 90 As shown by the distribution of the indicine Y-chromosomes 41 and microsatellite analysis, zebu bulls were crossed in several South American Criollo populations. 60,[91][92][93] Today, Brazil holds the largest commercial cattle population worldwide, with 200 million heads.…”