Efeitos da debicagem convencional e holandesa no desempenho de postura e viabilidade de poedeiras em um experimento não replicado com medidas repetidas

Abstract

The creation of laying hens is usually done in cages with highdensity thatmay cause stress in birds, leading to cannibalism, feather plucking and egg pecking. In an attempt to solve these problems,a procedure of beak trimming of the bird called debeaking is performed. This study aimed to evaluate using statistical parametric and non-parametric techniques if two types of beak trimming, the conventional hot blade beak trimming method and V debeaking have significant effects on egg production and viability of three lineages of commercial laying hens: Hy-Line, Dekalb-White and Lohmann-LSL. It were used the non parametric Friedman and Wilcoxon tests, which are suitable when the data are correlated. The characteristics analyzed were type of debeaking, chicken lineage, chicken age, egg production percentage, accumulated egg production percentage and viability. The results showed that under conventional debeaking the Hy-Line birds have lower production, but higher viability; The Dekalb obtained higher accumulated production at the end of the experiment and higher viability, but it is not possible to affirm that it is more resistant throughout life, because it presents a high mortality rate atearlier stages. Under the effects of V debeaking, Hy-Line had impaired viability, but its egg production increased significantly, Dekalb-White presented better viability results when had the beak cut by this method and the Lohmann strain showed higher Egg production and greater viability with V debeaking.