Related GMR Articles
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
Given the important role of leptin in metabolism, we looked for a possible association of leptin and leptin receptor polymorphisms with carcass and growth traits in Nellore cattle. We examined associations of leptin and leptin receptor SNPs with ultrasound carcass (longissimus dorsi muscle area (ribeye area), backfat thickness and rump fat thickness and growth traits (weaning weight ... more
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
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
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
Meat quality is an important trait for the beef industry. Backfat thickness, ribeye area, and shear force are traits measured late in life, and the investigation of molecular markers associated with these traits can help breeding programs. In cattle, some polymorphisms have been related to production traits. Thus, the purpose of this study was to assess the presence of polymorphisms in ... more
A synergistic effect in the somatotropic axis (GH1-GHR-IGF1) was observed in 736 young Nelore (Bos indicus) bulls under ad libitum grass feeding conditions on irrigated pasture in central Brazil. Stepwise substitution of shorter alleles of the promoter region of the growth hormone gene (GH1) and the P1 promoter of the GH1 receptor gene (GHR ... 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