Produtividade de frangos de corte em diferentes períodos de calor

Abstract

The productive losses due to heat stress suffered by broiler chickens generate economic losses being a great concern in the poultry chain. 2014 year was the warmest on record and was accompanied by the report of severe losses in broiler chickens. This study aimed to characterize the differences between two periods of heat from bioclimatic and husbandry point of view, quantify the potentials of air temperature reduction and determine husbandry and meteorological variables related to higher mortality of broiler chickens between periods I (11/01/2012-02/14/2013) and II (11/01/2013-02/14/2014). The results that are part of this dissertation are presented as scientific manuscripts. The first is a literature review that aimed to discuss the genetic evolution and the need for air-conditioning systems due to heat stress in broiler chickens; the second measures the impact on potentials of air temperature reduction and mortality of broiler chickens in poultry exposed in two different periods of heat; and the third evaluates the performance of broiler chickens housed in these two periods of heat. There was difference between the periods, being period II the hottest. The exhibition of broiler chickens housed in poultry with minimal air-conditioning for a period over 669,5h thermal discomfort caused higher mortality. Over periods of 548 hours ITU greater than or equal to 23° C caused an increase in mortality of broiler chickens. The study of meteorological and productive data can assist in understanding productive events in poultry of broiler chickens, with temperatures and humidity measures outside the premises, helping to identify the worst potential conditions of comfort of poultry related to the increase in lots of mortality percentages of broiler chickens. The cooling potential of an evaporative system would not be able to maintain comfort temperatures in atypical conditions observed in period II.