46 research outputs found
Estudo de heterogeneidade de variâncias na avaliação genética de bovinos de corte da raça Nelore
Genetic divergence between genotypes of forage peanut in relation to agronomic and chemical traits
Genetic parameters for milk yield, lactation length and calving intervals of Murrah buffaloes from Brazil
Comparação de modelos de regressão aleatória para estimação de parâmetros genéticos em caprinos leiteiros
Efeitos da Insulação Escrotal sobre a Biometria Testicular e Parâmetros Seminais em Carneiros da Raça Santa Inês Criados no Estado do Ceará
Invasão biológica de Artocarpus heterophyllus Lam. (Moraceae) em um fragmento de Mata Atlântica no Nordeste do Brasil: impactos sobre a fitodiversidade e os solos dos sítios invadidos
Humic Haplustox under different land uses in a high altitude environment in the Agreste region of Pernambuco, Brazil
Caracterização estrutural e status de conservação do estrato herbáceo de dunas da Praia de São Marcos, Maranhão, Brasil
Buffalos milk yield analysis using random regression models
Data comprising 1,719 milk yield records from 357 females (predominantly Murrah breed), daughters of 110 sires, with births from 1974 to 2004, obtained from the Programa de Melhoramento Genético de Bubalinos (PROMEBUL) and from records of EMBRAPA Amazônia Oriental - EAO herd, located in Belém, Pará, Brazil, were used to compare random regression models for estimating variance components and predicting breeding values of the sires. The data were analyzed by different models using the Legendre’s polynomial functions from second to fourth orders. The random regression models included the effects of herd-year, month of parity date of the control; regression coefficients for age of females (in order to describe the fixed part of the lactation curve) and random regression coefficients related to the direct genetic and permanent environment effects. The comparisons among the models were based on the Akaike Infromation Criterion. The random effects regression model using third order Legendre’s polynomials with four classes of the environmental effect were the one that best described the additive genetic variation in milk yield. The heritability estimates varied from 0.08 to 0.40. The genetic correlation between milk yields in younger ages was close to the unit, but in older ages it was low