Genetic parameters for milk yield of Bubalus bubalis using unadjusted and adjusted milk production for days in milk.

The objectives of this study were to estimate genetic parameters for unadjusted and adjusted milk production for 270 and 305 days of lactation and, subsequently, to verify the coincidence of rank of 2%, 5%, 20% and 40% best sires selected based on both models. Complete lactations from 90 or 150 days of lactation to 270 or 350 days of lactation were considered in the analyses. Milk production was adjusted for lactation length by multiplicative correction factors, or by including lactation length as a covariable in the model. Heritabilities, genetic correlations and breeding values were estimated for each trait, and variance and covariance components were estimated by restricted maximum likelihood methodology. Heritability estimates varied from 0.16 to 0.27. Genetic correlations between unadjusted and adjusted milk production for lactation length were higher than 0.64. Heritabilities for adjusted milk production were higher than heritabilities for unadjusted milk production for lactation length. In situations with high selection intensity, probably, modifications will happen in the rank of bulls and/or in the bulls chosen for mating if records are adjusted or unadjusted for 305 days

Water buffalo genome characterization by the Illumina BovineHD BeadChip

To define the best strategies for genomic association studies and genomic selection, it is necessary to determine the extent of linkage disequilibrium (LD) and the genetic structure of the study population. The current study evaluated the transference of genomic information contained in the Illumina BovineHD BeadChip from cattle to buffaloes, and assessed the extent of the LD in buffaloes. Of the 688,593 bovine single nucleotide polymorphism (SNP) that were successfully genotyped from the 384 buffalo samples, only 16,580 markers were polymorphic, and had minor allele frequencies greater than 0.05. A total of 16,580 polymorphic SNPs were identified, which were uniformly distributed throughout the autosomes, because the density and mean distance between markers were similar for all autosomes. The average minor allele frequency for the 16,580 SNPs was 0.23. The overall mean LD for pairs of adjacent markers was 0.29 and 0.71, when measured as for r(2) and vertical bar D'vertical bar, respectively. The 16,580 polymorphic SNPs were matched to Bos taurus chromosome in the current bovine genome assembly (Btau 4.2), and could be utilized in association studies. In conclusion, the Illumina BovineHD BeadChip contains approximately 16,580 polymorphic markers for the water buffalo, which are broadly distributed across the genome. These data could be used in genomic association and genomic selection studies; however, it might be necessary to develop a panel with specific SNP markers for water buffaloes

Parâmetros genéticos para características de tamanho e condição corporal, eficiência reprodutiva e longevidade em fêmeas da raça Canchim Genetic parameters for body size, condition score, reproductive and longevity traits in females of the Canchim breed

Objetivou-se estimar a herdabilidade das características tempo de permanência no rebanho (TPR) e idades ao primeiro (IDPP), ao segundo (IDSP) e ao terceiro (IDTP) parto e as correlações genéticas entre essas características e os pesos ajustado e não-ajustado para condição corporal, índice de tamanho corporal e condição corporal à primeira monta, ao primeiro parto e à idade adulta. Os componentes de variância e de co-variância foram estimados pelo método de máxima verossimilhança restrita livre de derivadas, utilizando-se análises uni e bicaracterísticas. Os modelos estatísticos incluíram o efeito genético aditivo direto, como aleatório, e o efeito fixo de grupo de contemporâneos. As estimativas de herdabilidade obtidas das análises unicaracterísticas foram 0,10 &plusmn; 0,05 (IDPP); 0,08 &plusmn; 0,05 (IDSP); 0,14 &plusmn; 0,06 (IDTP) e 0,06 &plusmn; 0,00 (TPR), e indicam que provavelmente as características apresentarão baixa resposta à seleção. A seleção para maior peso à idade adulta acarretará redução no tempo de permanência da fêmea no rebanho. A seleção para maiores pesos da fêmea à primeira monta, ao primeiro parto e à idade adulta não deve alterar significativamente as idades ao primeiro, ao segundo e ao terceiro parto. A seleção para os índices de tamanho corporal ou pesos ajustados para condição corporal provavelmente apresentará repostas correlacionadas nas características reprodutivas e de longevidade com tendências semelhantes, mas de maior magnitude em relação à seleção para peso sem ajuste.<br>The objectives of this study were to estimate heritability for culling age (TPR), ages at first (IDPP), at second (IDSP) and at third calving (IDTP) and genetic correlations of these traits with adjusted and unadjusted weights for condition score, body size indexes and condition score at first mating, at first calving and at mature age. Variance and covariance components were estimated by REML using univariate and bivariate models including the fixed effect of contemporary group and additive direct genetic and residual as random effects. Heritability estimates obtained from univariate analyses were 0.10 &plusmn; 0.05 (IDPP), 0.08 &plusmn; 0.05 (IDSP), 0.14 &plusmn; 0.06 (IDTP) and 0.06 &plusmn; 0.00 (TPR) and indicate low response to selection on these traits. Genetic correlation estimates suggest that selection for increasing mature weight will reduce culling age but for heavier weight at first mating, at first calving and at maturity will not significantly change ages at first, at second and at third calving. Selection on body size indexes and on cow weights adjusted for condition score may result in similar correlated responses for reproductive traits and longevity which would be higher than those from selection on unadjusted cow weights

Gene expression profile of intramuscular muscle in Nellore cattle with extreme values of fatty acid

Abstract Background Fatty acid type in beef can be detrimental to human health and has received considerable attention in recent years. The aim of this study was to identify differentially expressed genes in longissimus thoracis muscle of 48 Nellore young bulls with extreme phenotypes for fatty acid composition of intramuscular fat by RNA-seq technique. Results Differential expression analyses between animals with extreme phenotype for fatty acid composition showed a total of 13 differentially expressed genes for myristic (C14:0), 35 for palmitic (C16:0), 187 for stearic (C18:0), 371 for oleic (C18:1, cis-9), 24 for conjugated linoleic (C18:2 cis-9, trans11, CLA), 89 for linoleic (C18:2 cis-9,12 n6), and 110 genes for α-linolenic (C18:3 n3) fatty acids. For the respective sums of the individual fatty acids, 51 differentially expressed genes for saturated fatty acids (SFA), 336 for monounsaturated (MUFA), 131 for polyunsaturated (PUFA), 92 for PUFA/SFA ratio, 55 for ω3, 627 for ω6, and 22 for ω6/ω3 ratio were identified. Functional annotation analyses identified several genes associated with fatty acid metabolism, such as those involved in intra and extra-cellular transport of fatty acid synthesis precursors in intramuscular fat of longissimus thoracis muscle. Some of them must be highlighted, such as: ACSM3 and ACSS1 genes, which work as a precursor in fatty acid synthesis; DGAT2 gene that acts in the deposition of saturated fat in the adipose tissue; GPP and LPL genes that support the synthesis of insulin, stimulating both the glucose synthesis and the amino acids entry into the cells; and the BDH1 gene, which is responsible for the synthesis and degradation of ketone bodies used in the synthesis of ATP. Conclusion Several genes related to lipid metabolism and fatty acid composition were identified. These findings must contribute to the elucidation of the genetic basis to improve Nellore meat quality traits, with emphasis on human health. Additionally, it can also contribute to improve the knowledge of fatty acid biosynthesis and the selection of animals with better nutritional quality