Publications by authors named "Sarah L C Meirelles"

The Mangalarga Marchador (MM) horse breed has expressive importance in the Brazilian economy. Thus, the aim of this study was to investigate diversity in the MM breed. A database with a total of 3,193 genotyped horses was used (MM, n = 2,829; Andalusian - AND, n = 67; Pure Blood Lusitano - LUS, n = 43; English Thoroughbred - THO, n = 54; Arabian - ARA, n = 99; Campolina - CAM, n = 61; and Mangalarga - MAN, n = 40) for 13 microsatellite.

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Analysis of a large number of markers is crucial in both genome-wide association studies (GWAS) and genome-wide selection (GWS). However there are two methodological issues that restrict statistical analysis: high dimensionality (p≫n) and multicollinearity. Although there are methodologies that can be used to fit models for data with high dimensionality (eg, the Bayesian Lasso), a big problem that can occurs in this cases is that the predictive ability of the model should perform well for the individuals used to fit the model, but should not perform well for other individuals, restricting the applicability of the model.

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Knowledge of thermoregulatory responses in taurine cattle contribute to identification of animals most adapted to heat and productive when raised under Brazilian climate. The objectives were to verify the morphological and physiological responses related to adaptation to heat of taurine breeds raised under in Brazilian meteorological conditions in different seasons of the year and day periods, and to detect differences within and between breeds to know breed is most adapted. Measurements were made of 74 young bulls (n = 31 Angus; n = 43 Simmental) for the morphological traits: hair length (HL), number of hairs (NH), and coat thickness (CT); and for the physiological traits: respiratory rate (RR) and hair coat surface temperature (ST).

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Background: Beef cattle breeding programs in Brazil have placed greater emphasis on the genomic study of reproductive traits of males and females due to their economic importance. In this study, genome-wide associations were assessed for scrotal circumference at 210 d of age, scrotal circumference at 420 d of age, age at first calving, and age at second calving, in Canchim beef cattle. Data quality control was conducted resulting in 672,778 SNPs and 392 animals.

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Studies are being conducted on the applicability of genomic data to improve the accuracy of the selection process in livestock, and genome-wide association studies (GWAS) provide valuable information to enhance the understanding on the genetics of complex traits. The aim of this study was to identify genomic regions and genes that play roles in birth weight (BW), weaning weight adjusted for 210 days of age (WW), and long-yearling weight adjusted for 420 days of age (LYW) in Canchim cattle. GWAS were performed by means of the Generalized Quasi-Likelihood Score (GQLS) method using genotypes from the BovineHD BeadChip and estimated breeding values for BW, WW, and LYW.

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The potassium inwardly rectifying channel, subfamily J, member 11 (KCNJ11) gene was investigated as a candidate for meat tenderness based on the effects reported on muscle for KCNJ11 gene knockout in rat models and its position in a quantitative trait locus (QTL) for meat tenderness in the bovine genome. Sequence variations in the KCNJ11 gene were described by sequencing six amplified fragments, covering almost the entire gene. We identified single nucleotide polymorphisms (SNP) and validated them by different approaches, taking advantage of simultaneous projects that are being developed with the same Nelore population.

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Background: Meat quality involves many traits, such as marbling, tenderness, juiciness, and backfat thickness, all of which require attention from livestock producers. Backfat thickness improvement by means of traditional selection techniques in Canchim beef cattle has been challenging due to its low heritability, and it is measured late in an animal's life. Therefore, the implementation of new methodologies for identification of single nucleotide polymorphisms (SNPs) linked to backfat thickness are an important strategy for genetic improvement of carcass and meat quality.

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