Related GMR Articles
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 ... more
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 ... more
The bovine tick Rhipicephalus microplus is responsible for severe economic losses in tropical cattle production. Bos indicus breeds are more resistant to tick infestations than are Bos taurus breeds, and the understanding of the physiological mechanisms involved in this difference is important for the development of new methods of parasite control. We evaluated ... more
We evaluated and compared carcass traits and meat quality in Nellore cattle and F1 crosses between Nellore and Araguaia, where 17 individuals were from the Nellore group and 19 were ½ Nellore and ½ Araguaia crosses. All animals belonged to the same birth season and were raised in pasture systems under the same nutritional, environmental, and management conditions. When the animals ... more
The association between two single nucleotide polymorphisms (SNPs), T945M and UCP1SNP1, with hot carcass weight (HCW, kg, N = 618), longissimus dorsi muscle area (REA, cm2, N = 633), and backfat thickness (BF, mm, N = 625), measured in Nellore cattle in Brazil, was evaluated. Likelihood ratio tests were used to evaluate reduced (fixed effects of general mean, contemporary ... more
Data from purebred Brahman steers (N = 467) were used to study the association of single nucleotide polymorphisms (SNP) with carcass traits and measures of tenderness. Fall weaned calves were grazed and fed in a subtropical environment and then harvested for processing in a commercial facility. Carcass data were recorded 24 h postmortem. Muscle samples and primal ribs were obtained to measure ... more
Fourteen Brazilian Gir sire families with 657 daughters were analyzed for quantitative trait loci (QTL) on chromosome 6 affecting lactose and total solids. Cows and sires were genotyped with 27 microsatellites with a mean spacing between markers of 4.9 cM. We used a 1% chromosome-wide threshold for QTL qualification. A QTL for lactose yield was found close to marker MNB66 in three ... more
Growth hormone (GH) is a part of the somatotropic axis that controls metabolism, growth, development and aging in a wide range of animals. Mutations that reduce GH signaling have been associated with extended life spans and increased longevity in ways similar to what is observed in dietary restriction (DR) models. However, the mechanism by which DR works is not well understood. Here, we ... more
Survival or longevity is an economically important trait in beef cattle. The main inconvenience for its inclusion in selection criteria is delayed recording of phenotypic data and the high computational demand for including survival in proportional hazard models. Thus, identification of a longevity-correlated trait that could be recorded early in life would be very useful for selection ... more
We looked for possible associations of SNPs in genes related to protein turnover, with growth, feed efficiency and carcass traits in feedlot Nellore cattle. Purebred Nellore bulls and steers (N = 290; 378 ± 42 kg body weight, 23 months ± 42 days old) were evaluated for daily feed intake, body weight gain (BWG), gross feed efficiency, feed conversion ratio, partial efficiency of growth, ... more