Behavioral and physiological responses of different genetic lines of free-range broiler raised on a semi-intensive system

Abstract

The aim of the study was evaluate the ability of adaptation of seven different genetic lines of free range broilers to a semi-intensive raising system. Four hundred and twenty chicks of the Pescoco Pelado (PP), Carijo (CG), Colorpak (CPK), Tricolor (TRC), Caboclo (CBC), Gigante Negro (GNG) and Pesadao Vermelho (PS) genetic groups were used. At 28 days of age the birds were allowed access the paddocks and after three days of adaptation the monitoring of the animals has started, being performed behavioral visual observations from 07:00 to 17:00. Cloacal temperature (CT) and respiratory rate (RR) were collected once a week. The environment was monitored considering the temperature, relative humidity and black globe temperature at various points of the paddocks and the shed. The physiological variables were evaluated using a randomized complete block design with a split plot arrangement. Behavioral variables were analyzed using nonparametric Friedman test. Birds of Carijo and Colorpak genetic line presented greater RR, 34.6 mov/min and 36.0 mov/min respectively, compared to the birds of the Caboclo and Gigante Negro genetic line, 29.0 mov/min and 28.4 mov/min respectively. The average values of RR and CT for all genetic lines were higher in the afternoon. At 7:00 and 17:00 the foraging behavior was more intense. The Caboclo and Gigante Negro genetic line were those that stood out in the behavior of foraging, consequently, they are more able to adapt to the semi-intensive raising system.