The main selection aim in strains of laying hens is to increase egg production and egg quality and egg weight that may meet the requirements of the consumer market. In general, strains of laying hens are characterized by hierarchical mating (several dams by sire, each dam mated with only one sire), short generation intervals of 1.2 to 1.5 years, and discrete generations and several progenies by sire and by dam. This project aims estimate genetic parameters for partial and total egg production until 60 weeks, body weight, age at sexual maturity and egg weight and to study the multivariate relation among breeding values for all traits to provide tools for the genetic improvement program of a egg production strain. We will use records of two successive generations of performance of females arising from the strain denominated "DD", selected since 1988 mainly for egg production and developed by "Programa de Melhoramento Genético de Aves" of "EMBRAPA Suínos e Aves", Concórdia, SC. The total egg production will be evaluated individually by the sum of the number of eggs collected from 20th up to 60 weeks of age. Partial periods of egg production will be constituted by every month of egg production, tottaling 10 partial periods. Body weights were measured in females at 16 and at 60 weeks of age. Age at sexual maturity corresponds to the age in days when this female put his first egg. The egg weight were measured at 22 and at 28 weeks of age. The (co) variance components will be estimated by Restricted Maximum Likelihood under multi-trait animal model. The general model will include the random effects additive genetic and residual and the fixed effect of generation, if there is significant influence (p <0.05 ) of this effect on the traits. Multivariate analysis by principal components will be conducted using breeding values for partial and total egg production up 60 weeks of age, egg weight, body weight and age at first egg.
News published in Agência FAPESP Newsletter about the scholarship: