Feedlot performance, feed efficiency and carcass traits in Nellore cattle selected for postweaning weight

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Meta-análise de parâmetros genéticos relacionados ao consumo alimentar residual e a suas características componentes em bovinos

The objective of this work was to estimate, by meta-analysis, the heritability (h(2)) and the genetic (r(g)) and phenotypic (r(f)) correlations of residual feed intake (RFI), and of its component traits in beef cattle from 19 breeds or genetic groups. Twenty-two scientific papers published from 1963 to 2011, from eight countries, totaling 52,637 cattle of ages from 28 days up to slaughter, were evaluated. The estimates of RFI, dry matter intake (DMI), average daily gain (ADG) and metabolic weight (BW0.75) were weighted by the inverse of sample variance. The variation between studies of h(2) for each trait was analyzed by weighted least squares. The effects of sex, country and breed were significant for h(2) of RFI, explaining 67% of variation between studies. For DMI, country and breed effects were significant and explained 96% of variation. Pooled estimates of h(2) were: 0.255+/-0.008, 0.278+/-0.012, 0.321+/-0.015, and 0.397+/-0.032 for RFI, DMI, ADG and BW0.75, respectively. Pooled estimates of genetic and phenotypic correlations were low between RFI and ADG and between RFI and BW0.75 (from -0.021+/-0.034 to 0.025+/-0.035), and moderate between RFI and DMI (0.636+/-0.035 and 0.698+/-0.041) and between DMI, ADG and BW0.75 (0.441+/-0.062 to 0.688+/-0.032). The trait RFI has lower heritability estimates than its components.

Meat quality of young Nellore bulls with low and high residual feed intake

Fifty-nine Nellore bulls from low and high residual feed intake (RFI) levels were studied with the objective of evaluating meat quality traits. Animals were slaughtered when ultrasound-measured backfat thickness reached 4. mm, and samples of Longissimus were collected. A mixed model including RFI as fixed effect and herd and diet as random effects was used, and least square means were compared by t-test. More efficient animals consumed 0.730. kg dry matter/day less than less efficient animals, with similar performance. No significant differences in carcass weight, prime meat cuts proportion, chemical composition, pH, sarcomere length, or color were observed between RFI groups. Shear force, myofibrillar fragmentation index and soluble collagen content were influenced by RFI, with a higher shear force and soluble collagen content and a lower fragmentation index in low RFI animals. Feedlot-finished low RFI young Nellore bulls more efficiently convert feed into meat, presenting carcasses within quality standards. © 2012 Elsevier Ltd.

Expressão de genes relacionados à função mitocondrial em bovinos Nelore extremos para consumo alimentar residual

Pós-graduação em Genética e Melhoramento Animal - FCAV

Caracterização do consumo alimentar residual e relações com desempenho e características de carcaça de bovinos nelore

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Eficiência alimentar e desempenho de bovinos nelore selecionados para peso pós-desmame

Pós-graduação em Zootecnia - FMVZ

Genome-wide association analysis of feed intake and residual feed intake in Nellore cattle

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cluster and meta-analyses of genetic parameters for feed intake traits in growing beef cattle

A data set based on 50 studies including feed intake and utilization traits was used to perform a meta-analysis to obtain pooled estimates using the variance between studies of genetic parameters for average daily gain (ADG); residual feed intake (RFI); metabolic body weight (MBW); feed conversion ratio (FCR); and daily dry matter intake (DMI) in beef cattle. The total data set included 128 heritability and 122 genetic correlation estimates published in the literature from 1961 to 2012. The meta-analysis was performed using a random effects model where the restricted maximum likelihood estimator was used to evaluate variances among clusters. Also, a meta-analysis using the method of cluster analysis was used to group the heritability estimates. Two clusters were obtained for each trait by different variables. It was observed, for all traits, that the heterogeneity of variance was significant between clusters and studies for genetic correlation estimates. The pooled estimates, adding the variance between clusters, for direct heritability estimates for ADG, DMI, RFI, MBW and FCR were 0.32 +/- 0.04, 0.39 +/- 0.03, 0.31 +/- 0.02, 0.31 +/- 0.03 and 0.26 +/- 0.03, respectively. Pooled genetic correlation estimates ranged from -0.15 to 0.67 among ADG, DMI, RFI, MBW and FCR. These pooled estimates of genetic parameters could be used to solve genetic prediction equations in populations where data is insufficient for variance component estimation. Cluster analysis is recommended as a statistical procedure to combine results from different studies to account for heterogeneity.

Consumo alimentar residual e produção de metano entérico de bovinos em confinamento e pastagem

Pós-graduação em Zootecnia - FCAV

Genetic parameter estimates for feed efficiency and dry matter intake and their association with growth and carcass traits in Nellore cattle

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Predição da emissão de metano entérico de bovinos Nelore

Pós-graduação em Zootecnia - FCAV

Análise do perfil da expressão de genes candidatos com a eficiência alimentar de animais da raça Nelore

Pós-graduação em Genética e Melhoramento Animal - FCAV

Global liver gene expression differences in Nelore steers with divergent residual feed intake phenotypes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Expression of genes related to mitochondrial function in Nellore cattle divergently ranked on residual feed intake

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo de associação entre polimorfismos de base única com características de eficiência de conversão, consumo e desempenho em bovinos da raça Nelore

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)