Effects of inbreeding on production traits and genetic evaluations in Guzerá beef cattle raised under tropical conditions.

The objectives of this study were to evaluate the influence of inbreeding on growth traits and body measurements, as well as on the estimation of genetic parameters and genetic trends in Guzerá cattle. Phenotypic records of 4,212 animals selected for postweaning weight from Guzerá Breeding Program of Advanced Beef Cattle Research Center were utilized. The pedigree file contained records from 7,213 animals born from 1928 to 2019.

Understanding nitrogen dynamics in the Brazilian beef industry: A comprehensive decadal analysis.

Brazil stands as a prominent beef producer and exporter, witnessing major transformations and expansions in its production chain over the past 20 years. These changes have prompted concerns regarding waste generation and environmental pressure. This study employs material flow analysis (MFA) to quantify nitrogen flows throughout the cattle slaughter process and subsequent beef consumption in Brazil, spanning from 2011 to 2021.

Analysis of residual feed intake in Nellore bulls of different ages, rib eye area, and backfat thickness.

The aim of the present study was to use different models that include body composition phenotypes for the evaluation of residual feed intake (RFI) in Nellore bulls of different ages. Phenotypic and genotypic data of bulls that had participated in feed efficiency tests of a commercial (COM) and an experimental (EXP) herd between 2007 and 2019 were used. The mean entry age in the two herds was 645 and 279 days, respectively.

Different selection practices affect the environmental sensitivity of beef cattle.

The objective of the present study was to evaluate the effects of different selection practices on the environmental sensitivity of reproductive and growth traits in males and females of three Nellore selection lines [control (NeC), selection (NeS), and traditional (NeT) lines]. Moreover, genetic trends for the intercept and slope were estimated for each line, and the possible reranking of sires was examined. A total of 8,757 records of selection weight (SW), 3,331 records of scrotal circumference (SC), and 2,311 records of days to first calving (DFC) from Nellore cattle born between 1981 and 2017 were analyzed.

Animals selected for postweaning weight gain rate have similar maintenance energy requirements regardless of their residual feed intake classification.

Data of comparative slaughter were used to determine Nellore bulls' net energy requirements classified as efficient or inefficient according to residual feed intake (RFI) and selection lines (SL). Sixty-seven Nellore bulls from the selected (SE) and control (CO) lines of the selection program for postweaning weight gain were used. The animals underwent digestibility trials before being submitted to the finishing trial.

Genetic association among feeding behavior, feed efficiency, and growth traits in growing indicine cattle.

This study aimed to estimate genetic parameters, including genomic data, for feeding behavior, feed efficiency, and growth traits in Nellore cattle. The following feeding behavior traits were studied (861 animals with records): time spent at the feed bunk (TF), duration of one feeding event (FD), frequency of visits to the bunk (FF), feeding rate (FR), and dry matter intake (DMI) per visit (DMIv). The feed efficiency traits (1,543 animals with records) included residual feed intake (RFI), residual weight gain (RWG), and feed conversion (FC).

Association between residual feed intake, digestion, ingestive behavior, enteric methane emission and nitrogen metabolism in Nellore beef cattle.

This study aimed to evaluate nutrient intake and digestibility, enteric methane emission and nitrogen utilization efficiency in Nellore cattle ranked by residual feed intake (RFI). Twenty-four Nellore bulls at 466 ± 24 days of age and with 352 ± 14.6 kg of body weight, classified as low and high RFI, were evaluated.

Genome-wide identification of runs of homozygosity islands in the Gyr breed (Bos indicus).

Runs of homozygosity (ROH) are contiguous homozygous regions of the genome. These regions can be used to identify genes associated with traits of economic interest, as well as inbreeding levels. The aim of the present study was to analyse the length and distribution of ROH islands in Gyr cattle and to identify genes within these regions.

Linkage disequilibrium and effective population size in Gir cattle selected for yearling weight.

Linkage disequilibrium (LD) plays an important role in genomic selection and mapping of quantitative trait loci (QTL). This study investigated the pattern of LD and effective population size (N ) in Gir cattle selected for yearling weight. For this purpose, 173 animals with imputed genotypes (from 18 animals genotyped with the Illumina BovineHD BeadChip and 155 animals genotyped with the Bovine LDv4 panel) were analysed.

Relationship between performance, metabolic profile, and feed efficiency of lactating beef cows.

Twenty-seven Nellore cow-calf pairs were submitted for feed efficiency testing. The animals were weighed every 21 ± 5 days to obtain metabolic body weight (BW) and average daily gain (ADG). Subcutaneous fat thickness (SFT; at 20, 83, 146, and 176 days post-calving); milk yield and components (63, 85, and 151 days); levels of glucose, cholesterol, triglycerides, β-hydroxybutyrate, albumin, urea, creatinine, calcium, phosphorus, magnesium, insulin, and cortisol (15, 41, 62, and 124 days); and ingestive behavior were evaluated.

Assessing genetic architecture and signatures of selection of dual purpose Gir cattle populations using genomic information.

Gir is one of the main cattle breeds raised in tropical South American countries. Strong artificial selection through its domestication resulted in increased genetic differentiation among the countries in recent years. Over the years, genomic studies in Gir have become more common.

Correction: Genomic Regions Associated with Feed Efficiency Indicator Traits in an Experimental Nellore Cattle Population.

[This corrects the article DOI: 10.1371/journal.pone.

Digestion and metabolism of low and high residual feed intake Nellore bulls.

Understanding the reasons why animals of similar performances have different feed requirements is important to increase profits for cattle producers and to decrease the environmental footprint of beef cattle production. This study was carried out aiming to identify the associations between residual feed intake (RFI) and animal performance, nutrient digestibility, and blood metabolites related to energy balance of young Nellore bulls during the finishing period. Animals previously classified as low (n = 13) and high RFI (n = 12), with average initial body weight of 398 kg and age of 503 days were used.

Genome-Wide Association Study for Carcass Traits in an Experimental Nelore Cattle Population.

The purpose of this study was to identify genomic regions associated with carcass traits in an experimental Nelore cattle population. The studied data set contained 2,306 ultrasound records for longissimus muscle area (LMA), 1,832 for backfat thickness (BF), and 1,830 for rump fat thickness (RF). A high-density SNP panel (BovineHD BeadChip assay 700k, Illumina Inc.

Genomic Regions Associated with Feed Efficiency Indicator Traits in an Experimental Nellore Cattle Population.

The objective of this study was to identify genomic regions and metabolic pathways associated with dry matter intake, average daily gain, feed efficiency and residual feed intake in an experimental Nellore cattle population. The high-density SNP chip (Illumina High-Density Bovine BeadChip, 777k) was used to genotype the animals. The SNP markers effects and their variances were estimated using the single-step genome wide association method.

Phenotypic and Genetic Correlations of Feed Efficiency Traits with Growth and Carcass Traits in Nellore Cattle Selected for Postweaning Weight.

This study evaluated phenotypic (rph) and genetic correlations (rg) between 8 feed efficiency traits and other traits of economic interest including weight at selection (WS), loin-eye area (LEA), backfat thickness (BF), and rump fat thickness (RF) in Nellore cattle. Feed efficiency traits were gain:feed, residual feed intake (RFI), residual feed intake adjusted for backfat thickness (RFIb) and for backfat and rump fat thickness (RFIsf), residual body weight gain (RG), residual intake and body weight gain (RIG), and residual intake and body weight gain using RFIb (RIGb) and RFIsf (RIGsf). The variance components were estimated by the restricted maximum likelihood method using a two-trait animal model.

Feed efficiency, blood parameters, and ingestive behavior of young Nellore males and females.

This study aimed to evaluate differences in efficiency of feed utilization between young Nellore males and females by comparing growth traits, feed intake, blood parameters, and ingestive behavior of the animals. Data from 768 Nellore males and females that participated in eight performance tests for individual feed intake evaluation were used. Performance and feed efficiency measures, efficiency-related hematological, metabolic and hormonal variables, and data regarding ingestive behavior were collected.