Heat Stress in Broilers and the Need of Climatization Systems

Abstract

Broilers have better production rates when housed in thermal comfort conditions, outside of this zone the poultry need to maintain homeothermy. The heat production and thermal exchanges are related to body weight and available surface for heat exchange. The genetic evolution of broilers ensured high production with improvement in the feed conversion and reducing the slaughter time. The faster weight gain difficult sensible heat exchange, increasing the needs for climatization systems, in days with high temperatures. Changes in heat waves frequency and days with extreme temperatures are challenging situations for ventilation and evaporative cooling systems in broiler facilities. This review discusses heat exchanges of broilers and the challenges in maintaining the thermal comfort zone in poultry facilities, in a reality of increase of heat stress conditions. Keywords: welfare, heat production, body surface ESTRESSE POR CALOR EM FRANGOS DE CORTE E A NECESSIDADE DE SISTEMAS DE CLIMATIZAÇÃO RESUMOFrangos de corte apresentam melhores índices produtivos quando alojados em condições de conforto térmico, fora desta faixa necessitam manter a homeotermia. A produção de calor e as trocas térmicas estão relacionadas com o peso corporal da ave e a área de superfície disponível para as trocas térmicas. A evolução genética do frango de corte garantiu maior produção de carne com melhor conversão alimentar e menor tempo para o abate. A evolução do ganho de peso dificultou as trocas térmicas sensíveis aumentando a necessidade de sistemas de climatização, em dias com temperaturas elevadas. Estimativas para mudanças na frequência de ondas de calor e dias com temperaturas extremas são situações de desafio para os sistemas de ventilação e resfriamento evaporativo de aviários. Esta revisão discute as trocas térmicas de frangos de corte e os desafios em manter a zona de conforto térmico nas edificações em uma realidade de aumento de condições causadoras de estresse por calor.

Organic zinc and vitamin E supplementation for broiler chickens under natural heat stress conditions

“…When birds are under heat stress, there is an increase in energy demand to ensure the maintenance of homeothermia. In addition, when stress is lasting, there is an increase in glycogenesis, production of ketone bodies, gastric lesions, suppression of appetite, and impairment of immunological mechanisms, resulting in a drop in productivity (SANTOS et al 2017).…”

Efficiency of cooling systems in broiler houses during hot days

“…The effects of weather events and thermal vulnerability of broiler houses are more significant in broilers older than 28 days, requiring the maximum capacity of cooling systems (CHEPETE et al, 2005;MARCHINI et al, 2007;ABREU et al, 2012;CASSUCE et al, 2013;COUMOU & ROBINSON, 2013). The occurrence of climatic extremes requires efficient cooling systems to maintain thermal comfort conditions inside the broiler house (OSORIO et al, 2016;SANTOS et al, 2017;COELHO et al, 2019). Tunnel ventilation (in positive or negative pressure) and cooling systems are alternatives for controlling the airspeed and the inside relative humidity (RH) in facilities (BUCKLIN et al, 2009;SALAS et al, 2016), thus mitigating the effects of heat stress in broilers by the loss of convective and latent heat.…”

Representativeness of the field of rural buildings and ambience in Brazilian journals / Representatividade do campo dos edifícios rurais e do ambiente nas revistas brasileiras

“…The impact that a rural production building can cause on the production process itself, on the product and the workers, is very expressive. Especially in animal production, the quality of the physical environment 2,3,11,12,[21][22][23][24][25][26][27][28][29][30] (rooms, population density, construction materials, the ease of nutritional and sanitary management) and the quality of the indoor environment (pollutant gases, particulate materials, microorganisms, temperature and relative humidity, ventilation 11,[31][32][33] ) are distinctive factors in the quality of the process and product.…”