Characterization of the Thermal Environment and Poultry Performance in Different half-acclimatized Facility Systems under Brazilian Winter Conditions

Abstract

Abstract: The initial management in broiler chicken production is fundamental for productive performance, whereas their deficient development can affect negatively the uniformity of the lot and reduce its final performance. This study was conducted to diagnose and analyze the thermal environmental comfort and the zootechnic performance of broiler chickens grown in two different half-acclimatized ventilation systems: one with negative pressure (NPS) and the other with positive pressure (PPS), during the warming period under winter conditions on southern Brazil. Aiming at the characterization of the thermal environment, an evaluation was performed for temperature, air relative humidity and Black Globe Temperature Index and humidity (BGHI) in the first weeks of the fowls' life during the warming phase. The measurements were accomplished at the fowl levels. The animal's performance was evaluated on the basis of the average alive weight, food conversion and mortality rate, by using the average of the values obtained during two complete growing cycles. It was observed that in the first week of life, the temperature averages were below the range corresponding to the animal's thermal comfort, which is below 32 oC. In both treatments, the air relative humidity was between 65 and 70%, those are considered ideal levels for fowls comfort. The BGHI values were observed to be always superior in NPS with the widest amplitudes in the second week of life. In relation to the poultry productive performance indexes, it was found that all were within the range considered as desirable, relative to the average values obtained by the Brazilian broiler chicken production.