Avaliação do crescimento de codornas de corte utilizando modelos de regressão aleatória / Evaluation of quail meat growth using random regression models

AUTOR(ES)

Cristina Moreira Bonafé

DATA DE PUBLICAÇÃO

2008

RESUMO

The data used in this study originates from 26835 and 27447 observations, from 3909 and 4040 meat quails of the UFV-1 and UFV-2 lineage, respectively, pertaining to the Program of Genetic Improvement of Poultry of the Federal University of Viçosa. The characteristic physical weight was evaluated in the two lineages, 1, 7, 14, 21, 28, 35 and 42 days of age, through random regression models. The modeling of the residual variance was evaluated first through classes of age, grouped as follows: CL1: homogeneous; CL2: 1 and 7-42 days; CL3: 1, 7 and 14-42 days; CL4: 1, 7, 14 and 21- 42 days; CL5: 1, 7, 14, 21 and 28-42 days; CL6: 1, 7, 14, 21, 28 and 35-42 days; CL7: 1, 7, 14, 21, 28, 35 and 42 days old and, subsequently, the adjustment order of the Legendre polynomial functions applied to the random regression models, were gradually increased (orders varying from 3 to 6), aiming to determine the least order of each random effect, which is necessary to describe (co)variance structures in function of time. Comparing the residue models through classes, increases were found in Loge L, significant (P <0,01) to the Liklihood Ratio Test (LRT), with an increase in the number of heterogeneous classes (CL7). In accordance with all the criteria used to evaluate the adjustment quality, the model considering homogeneity (CL1) of residual variances appeared unsuitable, as well as unicharacteristic (UNI) analysis model. The variance estimates, herdability and correlations were influenced by the modeling of the residual varaiance and by the polynomial adjustment function. The use of a Legendre polynomial function with orders 6 for a straight additive genetic effect and 5 for a constant animal effect, for lineage UFV-1 and 6 for both random effects on lineage UFV-2, must be used in the genetic evaluation of the growth curve of these quails. So, the heterogeneity use of residual variance and the appropriate adjustment order to each random effect to model the variances associated to the curve of the growth quail meat if it is necessary.

ASSUNTO(S)

quail meat random regression genetic evaluation avaliação genética codorna de corte genetica e melhoramento dos animais domesticos regressão aleatória

Documentos Relacionados

• Avaliação da produção de leite em cabras da raça Saanen utilizando modelos de regressão aleatória
• Estimativas da trajetória genética do crescimento de codornas de corte utilizando modelos de regressão aleatória
• Avaliação do crescimento e de modelos de regressão aleatória em caprinos da raça Alpina
• Estudo da produção de leite de caprinos utilizando modelos de regressão aleatória
• Genetic evaluation of dairy buffaloes using random regression model