Related GMR Articles
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
Meat quality is being increasingly demanded by consumers in recent years. Several factors can affect meat quality, ranging from animal traits such as breed and genetic heritage to pre- and post-slaughter processes. This study investigated the influence of Nellore bulls on carcass and meat quality traits. We used 475 young uncastrated males, the progeny of 54 bulls, to evaluate ... 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
Leptin is a hormone that affects the regulation of feed intake, energy balance and body composition in mammals. Several polymorphisms in the bovine leptin gene have been associated with phenotypic variance of these traits. We evaluated two known single nucleotide polymorphisms (SNPs) in the leptin gene of 253 grazing Brangus steers. Brangus is a 5/8 Angus-3/8 Brahman composite. Data were ... more
The objective of the present study was to estimate (co)variance components for length of productive life (LPL) and some alternative reproductive traits of 6-year-old Nellore cattle. The data set contained 57,410 records for age at first calving from Nellore females and was edited to remove animal records with uncertain paternity and cows with just one piece of calving information. Only animals ... more
The aim of the present study was to evaluate the heterosis effects on weaning weight at 205 days (WW, n = 146,464), yearling weight at 390 days (YW, n = 69,315) and weight gain from weaning to yearling (WG, n = 59,307) in composite beef cattle. The fixed models were: RM, which included contemporary groups, class of age of dam, outcrossing percentages for direct and maternal effects, and ... more
With the aim of estimating the coefficient of heritability of average annual productivity of Nellore cows (COWPROD), a data set from 24,855 animals with known pedigree was analyzed. COWPROD is defined as the amount (in kilograms) of weaned calves produced yearly by one cow during her remaining time in herd ignoring a fixed period of 365 days. COWPROD was calculated regarding three standards: a ... more
The somatotropic axis is a major regulatory pathway of energy metabolism during postnatal growth in mammals. Genes involved in this pathway influence many economically important traits. The association of selected SNPs in these genes with carcass traits was examined in grazing Brangus steers. These traits included final live weight, ultrasound backfat thickness (UBFT), rib-eye area, ... more
We estimated genetic parameters for various phases of body and testicular growth until 550 days of age in Nelore cattle, using Bayesian inference, including correlation values and error estimates. Weight and scrotal records of 54,182 Nelore animals originating from 18 farms participating in the Brazilian Nelore Breeding Program (PMGRN) were included. The following traits were measured: ... more