Search

Characterized by the incomplete development of the germinal epithelium of the seminiferous tubules, Testicular hypoplasia (TH) leads to decreased sperm concentration, increased morphological changes in sperm and azoospermia. Economic losses resulting from the disposal of affected bulls reduce the efficiency of meat production systems. A genome-wide association study and functional analysis were performed to identify genomic windows and the underlying positional candidate genes associated with TH in Nellore cattle. Phenotypic and pedigree data from 207,195 animals and genotypes (461,057 single nucleotide polymorphism, SNP) from 17,326 sires were used in this study. TH was evaluated as a binary trait measured at 18 months of age. A possible correlated response on TH resulting from the selection for scrotal circumference was evaluated by using a two-trait analysis. Thus, estimated breeding values were calculated by fitting a linear-threshold animal model in a Bayesian approach. The SNP effects were estimated using the weighted single-step genomic BLUP method. Twelve non-overlapping windows of 20 adjacent SNP that explained more than 1% of the additive genetic variance were selected for candidate gene annotation. Functional and gene prioritization analysis of the candidate genes identified genes (KHDRBS3, GPX5, STAR, ERLIN2), which might play an important role in the expression of TH due to their known roles in the spermatogenesis process, synthesis of steroids and lipid metabolism.

O objetivo deste trabalho foi demonstrar a utilização da estatística como ferramenta para minimizar o risco em operações de hedge de boi gordo, tendo como base a série histórica de preços na cidade de Itapetinga no estado da Bahia. Os preços no mercado futuro foram obtidos junto ao Centro de Estudos Avançados em Economia Aplicada [CEPEA] Esalq/USP. Os preços do mercado físico foram levantados junto a Secretária da Agricultura, Pecuária, Irrigação, Pesca e Aquicultura [SEAGRI-BA]. Foi calculada a correlação entre os preços nos mercados físico e futuro com o objetivo de saber o quanto a variação de um acompanha a variação do outro. Foram calculadas as bases para todos os dias do período de tempo em análise, em seguida foram encontrados a média e o desvio padrão da base. Encontrado o risco de base das operações de hedge, tendo como referência a tabela da distribuição normal-padrão, foram simulados contratos de compra e venda diariamente no período de um ano, utilizando o conceito de custo de base para determinar o preço objetivo, aumentando a segurança nas operações. Sugeriu-se na prática encerrar algumas posições e assumir outras à medida que o mercado se movimenta a favor ou contra a posição do hedge. Desta forma, estratégias hedge em mercados futuros se mostram como excelentes opções para se precaver contra a variação de preços de boi gordo.

Made available in DSpace on 2020-12-10T17:02:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-12-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The research aim was to evaluate the genotype-environment interactions (GxE) through a study of the reaction norms of Nellore cattle raised in the North and Northeast regions of Brazil at the age at first calving (AFC), with scrotal circumference at 365 and 450 days of age (SC365 and SC450), gestation length (GL) and accumulated productivity (ACP). Bayes hierarchical models with defined parameters at structured levels or stages were used. The Markov chain Monte Carlo method was used to obtain genetic parameter estimates. The environmental gradient of each trait was defined using a 99% credibility interval of the contemporary group's solutions. The animal model showed a better fit for AFC data, and the two-step reaction norms model was the best for the other characteristics. Heritabilities were 0.21 +/- 0.01 for AFC; and ranged from 0.27 +/- 0.04 to 0.58 +/- 0.02, 0.26 +/- 0.05 to 0.57 +/- 0.02, 81 +/- 0.03 to 0.03 +/- 0.02, 0.05 +/- 0.02 to 0.86 +/- 0.03 along the environmental gradient for SC365, SC450, GL and ACP, respectively. Correlations between intercept and slope of the reaction norms allied with reaction norms graphic plots of the ten sires with the greatest number of calves suggest the presence of GxE complex for SC365 and SC450, and thcE scale effect for GL and ACP. However, high correlations between the environments indicate that the GxE for SC450 and ACP is of a low magnitude and its inclusion in genetic evaluations would not influence the population selection. State Univ Southwest Bahia, Itapetinga, BA, Brazil State Univ Southwest Bahia, Dept Biol Sci, Jequie, BA, Brazil Fed Inst Amapa, Porto Grande, Amapa, Brazil Natl Assoc Breeders & Researchers, Ribeirao Preto, SP, Brazil Univ Fed Ceara, Juazeiro Do Norte, Ceara, Brazil Sao Paulo State Univ Unesp, Sch Agr & Vet Sci, Jaboticabal, SP, Brazil Sao Paulo State Univ Unesp, Sch Agr & Vet Sci, Jaboticabal, SP, Brazil CAPES: 001

The objective of this research is to estimate the genetic parameters and covariance components for growth characteristics in cattle from Tabapua breed through random regression models (RRM). The estimates of covariance functions are considered nowadays, interesting alternatives to work with longitudinal data that allow the description of covariances changes due to time and prediction of variances and covariances along the growth curve. The RRM has been used to estimate the variance components and genetic parameters of milk production on the control day of the lactation curve and meat production in many species, including bodyweight of beef cattle and among these the cattle from Tabapua breed, enabling us to work with features of growth curves that are measured repeatedly during the animal's life, known as longitudinal data. These models used in genetic evaluation in cattle are considered special cases of covariance functions that allow estimation of coefficients of genetic covariance functions directly through the method of restricted maximum likelihood.