Análise de componentes principais em características de produção de aves de postura

Abstract

RESUMO -Para avaliar a possibilidade de descarte de variáveis de produção em 942 aves de postura por meio de componentes principais, visando eliminar características redundantes e de difícil mensuração, foram utilizados os dados obtidos Principal component analysis in laying hen production traitsABSTRACT -To assess the possibility of discarding production variables in 942 laying hens by principle component analysis to eliminate unnecessary and difficult to measure characteristics, data were obtained from laying hen lines of the genetic breeding program of the Universidade Federal de Viçosa. The traits analyzed were egg production rate (TP) from the 26 th to the 58 th week, individual mean weight at the 34 th (PMI 1 ), 42 th (PMI 2 ), 50 th (PMI 3 ), 58 th (PMI 4 ) and 66 th week (PMI 5 ); egg mean weight at the the 34 th (PMO 1 ), 42 nd (PMO 2 ), 50 th (PMO 3 ), 58 th (PMO 4 ) and 66 th weeks of age (PMO 5 ).Eight of the 11 principal components showed variance lower than 0.7 (eigenvalue lower than 0.7), suggesting 8 variables to discard. The discarded variables were those that showed the highest coefficients, in absolute value, from the last principal component because variables highly correlated with the principal components of smaller variance represent practically insignificant variation. The discarded variables presented significant simple linear correlation with the others, therefore, they were redundant. Based on these results, the following variables are recommended for use in future experiments: TP, PMI 1 , PMO 4 .

Egg production evaluation of laying hens by multivariate analysis

“…Paiva et al (2010) analyzed the average laying rate from 26 th to 58 th week of age and found that the rate of posture is an important feature for the selection of laying hens, since it has correlation with the first principal components. However, Abreu et al (1999) observed that the first component has high correlation with the total period of production (24 th to 56 th week of age), and the second principal component is more correlated with the number of eggs from 24 th to 32nd week and from 24 th to 40 th week of age.…”

“…To improve this relation, new methodologies to improve the selection process of laying hens have being studied, in order to maximize gains. In egg production evaluation, the information obtained by univariate analysis may be incomplete, especially when the variables are correlated (Paiva et al, 2010). The multivariate analysis evaluates a set of characteristics simultaneously taking into account the existence of correlation, evaluating more accurately the differences between the treatments (Cohen et al, 2003).…”

Utilização de dados parciais na seleção de codornas de corte para produção de ovos

“…Para o grupo genético UFV2, as estimativas de herdabilidade foram semelhantes às obtidas por Teixeira et al (2012) e Venturini et al (2012), porém inferiores às encontradas por Winter et al (2006) e Paiva et al (2010). Em trabalho com o mesmo grupo genético, Ribeiro et al (2012) encontraram estimativas que variaram de 0,20 a 0,25 para todos os períodos estudados.…”

“…Os valores observados (0,79 a 0,99) foram semelhantes aos encontrados por Winter et al (2006) em codornas japonesas (0,71 a 0,99), e aos encontrados por Paiva et al (2010) sobre galinhas poedeiras (0,67 a 0,94). Portanto, os dados desses períodos poderiam ser utilizados para seleção precoce.…”

“…Para UFV2, as estimativas de correlação genética variaram de 0,70 a 0,99 (Tabela 3). Esses valores são semelhantes aos encontrados por Winter et al (2006) e Paiva et al (2010) e superiores ao encontrados por Ribeiro et al (2012) e Venturini et al (2012. Essas Tabela 1.…”