Análise do ambiente em galpões de poedeiras comerciais telados

Abstract

Due to occurrences of the avian influenza viruses (H5N1 and H7N2), one of the demands made by the Ministry of Agriculture through the Normative Instruction No. 56 (MAPA, 2007) is the use of screens to completely surround the perimeter of conventional laying houses in order to improve bio-safety in the laying farms. In this context, the present study aimed at evaluating and comparing the use of screens in conventional laying houses for housing hens in order to improve health, welfare and safety of workers and animals. This research was conducted in a commercial laying farm, located in the south of Minas Gerais, Brazil, in two conventional laying houses, with half of its area surrounded by the screen and the other half kept fully open. Dekalb Brown (Laying house 1) and Hyline W -36 (Laying house 2) laying hens were housed in these laying houses and the thermo-acoustic and aerial variables were analyzed. The variables were collected at six measurement points in each region (with and without screens), with two points in each corridor (north, central and south). The results show that the use of screen changed the air flow within both laying houses studied, decreasing it in 38% in laying house 1 and 27% in laying house 2. It also changed the air temperature, the black globe temperature and humidity index and the enthalpy in a few periods of the day, making that these values were superior to those found in the areas without the screen, however, remaining within the recommended for the comfort of the hens. Regarding the noise level, concentrations of ammonia and carbon dioxide, the use of screens made these values rise within the two laying houses analyzed. However, the levels measured were inferior to those which offer health risks to the birds and workers. Therefore, the use of the screens surrounding the laying house altered the internal environment, though not enough to harm the housed animals or the farm workers.