Interação genótipo x ambiente em características avaliadas por ultrassom em bovinos da raça Canchim.

Foram avaliados 1.652 animais Canchim (5/8 Charolês + 3/8 zebu) e MA (filhos de touro Charolês em fêmeas ½ Canchim + ½ zebu) para área de olho de lombo (AOL) e espessura de gordura subcutânea (EGS) durante os anos de 2005 a 2010. Esses animais foram separados por sexo e por região de criação (São Paulo e Goiás) e então foi avaliado o efeito da interação genótipo-ambiente por meio de análises bi-características, utilizando-se modelo animal com efeitos fixos de grupo de contemporâneo, covariáveis lineares (idade, peso e heterozigose individual), além dos efeitos aleatórios aditivo direto e residual. A herdabilidade (h2a) para EGS em fêmeas (0,28) foi superior aos machos (0,04) e a correlação genética (0,49) indica que a característica é controlada de forma diferente em machos e fêmeas. A h2a para AOL por sexo (M=0,34 e F=0,38) e por região (SP=0,37 e GO=0,47) indica que a característica apresenta variância genética suficiente para responder à seleção nos diferentes ambientes estudados

Genetic parameters for carcass traits and body weight using a Bayesian approach in the Canchim cattle.

Correlation between genetic parameters and factors such as backfat thickness (BFT), rib eye area (REA), and body weight (BW) were estimated for Canchim beef cattle raised in natural pastures of Brazil. Data from 1648 animals were analyzed using multi-trait (BFT, REA, and BW) animal models by the Bayesian approach. This model included the effects of contemporary group, age, and individual heterozygosity as covariates. In addition, direct additive genetic and random residual effects were also analyzed. Heritability estimated for BFT (0.16), REA (0.50), and BW (0.44) indicated their potential for genetic improvements and response to selection processes. Furthermore, genetic correlations between BW and the remaining traits were high (P > 0.50), suggesting that selection for BW could improve REA and BFT. On the other hand, genetic correlation between BFT and REA was low (P = 0.39 ± 0.17), and included considerable variations, suggesting that these traits can be jointly included as selection criteria without influencing each other. We found that REA and BFT responded to the selection processes, as measured by ultrasound. Therefore, selection for yearling weight results in changes in REA and BFT

Análise de haplótipos em QTL associado ao conteúdo de ferro no músculo de bovinos Nelore.

Editores técnicos: João de Mendonça Naime, Caue Ribeiro, Maria Alice Martins, Elaine Cristina Paris, Paulino Ribeiro Villas Boas, Ladislau Marcelino Rabello

Preliminary studies for identification of SNPs associated with ribeye area in Canchim cattle.

A genome wide-association study (GWAS) was performed with 400 animals with extreme phenotypes for REA, using the RandomForest methodology. From this analysis, 7 SNPs in the 3,4989,224 to 3,689,224 interval of chromosome 27 (UMD 3.1) were identified as associated.ISAFG 2013. AB.36

Genome-enabled prediction of breeding values for feedlot average daily weight gain in nelore cattle.

Nelore is the most economically important cattle breed in Brazil, and the use of genetically improved animals has contributed to increase beef production efficiency. The Brazilian beef feedlot industry has grown considerably in the last decade, so the selection of animals with higher growth rates on feedlot has become quite important. Genomic selection could be used to reduce generation intervals and improve the rate of genetic gains. The aim of this study was to evaluate the prediction of genomic estimated breeding values for average daily gain in 718 feedlot-finished Nelore steers. Analyses of three Bayesian model specifications (Bayesian GBLUP, BayesA, and BayesCπ) were performed with four genotype panels (Illumina BovineHD BeadChip, TagSNPs, GeneSeek High and Low-density indicus). Estimates of Pearson correlations, regression coefficients, and mean squared errors were used to assess accuracy and bias of predictions. Overall, the BayesCπ model resulted in less biased predictions. Accuracies ranged from 0.18 to 0.27, which are reasonable values given the heritability estimates (from 0.40 to 0.44) and sample size (568 animals in the training population). Furthermore, results from Bos taurus indicus panels were as informative as those from Illumina BovineHD, indicating that they could be used to implement genomic selection at lower costs

Descriptive analysis of haplotypes in a population of Canchim beef cattle.

The aim in this study was to descriptively analyze haplotypes from a Canchim beef cattle population

Descriptive analysis of haplotypes in a population of Canchim beef cattle.

The aim in this study was to descriptively analyze haplotypes from a Canchim beef cattle population