ABSTRACT
Considering the need for providing the chickens with an adequate environment that could favor their maximum performance, especially at high density raising, this study aimed to compare the effects of two different thermal conditioning environmental systems (Tunnel Ventilation System, SVT, and Lateral Ventilation System, SVL, both associated to the internal nebulosity) on the poultry housing thermal comfort and, on the productive performance of broiler chickens under summer conditions of the Governador Valadares region of Minas Gerais State. The chickens were sheltered at a density of 14 broiler m-2, about 40% superior in relation to average of the region. The experiment was carried out at broiler age from 14 to 42 days, using two poultry houses with dimensions of 12.0 x 120.0 x 3.0 m that had identical construction characteristics and were oriented on the east- western direction, where the two cooling systems (SVT and SVL) were installed. The environmental thermal comfort was evaluated by the Black Globe Humidity Index (BGHI) and Radiant Heat Load (RHL), obtained at animal level, every 2 h, from 8 a.m. to 6 p. m. outside and inside the experimental poultry housing. The broiler productive performance was evaluated by ration consumption and weight gain, evaluated weekly. For both environmental conditioning systems, there were no significant differences in the ITGU and CTR thermal comfort indices. The mean results of the productive performance indices of the broilers in the SVT were better than in the SVL. When compared to the average performance indices obtained from earlier lots grown in the same experimental poultry housing under summer conditions, it was verified that the use of either environmental conditioning systems allowed a 40% rise in the broiler density. Besides, there was an improvement in the broiler performance shown by an increment in final live weight gain equal to 55 and 15 g broiler-1 for SVT and SVL, respectively, and a ration consumption of 4,31, 4,37 and 5,0 kg broiler-1 for SVT, SVL and the traditional poultry housing, respectively.
Key words:
poultry environment; high density; thermal comfort