Noise analysis to evaluate chick thermal comfort

Abstract

ABSTRACT:The relationship between thermal environment and chick performance has widely been evaluated, however the consideration that the assessment of the comfort may be estimated by interpreting both amplitude and frequency of bird vocalization under tropical housing conditions is a new concept. This research had as objective of estimating thermal comfort for chicks during the heating phase using this new concept. An experiment was carried out inside a climate controlled chamber (A) for establishing the behavioral pattern related to environmental temperature limits. Forty five chicks were reared inside a 2.3 m 2 box. A video camera was placed 2.0 m above the birds and the images were captured and registered in a computer. From the pattern determined in the controlled chamber an evaluation of the results was proceeded in a commercial broiler farm (experiment B) using similar bird density in order to validate the data. Environmental temperature, and both amplitude and frequency of the vocalizations of the chick group reared under heating were continuously recorded in both experiments. A correlation between group behavioral pattern and their vocalization, was found, evaluated not only by the noise amplitude but also by the noise frequency spectrum. When the thermal inertia is maintained by adequate use of curtains the birds vocalized less which is coincident with the low sudden variation of the temperature of the environmental. It was possible to estimate the thermal comfort for chicks at the heating stage by recording the amplitude and the frequency of the noise emitted by the reared group. Key words: broiler production, analysis of signals, thermal environment, behavior ANÁLISE DE RUÍDO PARA A AVALIAÇÃO DO CONFORTO TÉRMICO DE PINTINHOSRESUMO: A relação entre o ambiente térmico e o desempenho de pintinhos tem sido estudada, entretanto a consideração de que a medida de conforto térmico possa ser estimada pela interpretação da amplitude e da freqüência da vocalização, em condições tropicais de alojamento é um conceito novo. Esta pesquisa teve como objetivo estimar uma medida de bem-estar térmico para pintinhos em fase de aquecimento, pela medida de amplitude e freqüência do ruído emitido pelo grupo alojado. Inicialmente foi feito um experimento em câmara climática (A), para se estabelecer padrões de comportamento a partir de limites de temperatura ambiental. Foram alojados 45 pintos em um box de 2,3 m 2 . Uma câmera foi colocada a 2,0 m acima das aves e a captura das imagens foi registrada em um computador. A partir dos padrões determinados no primeiro experimento, foi feita uma avaliação desses resultados em uma granja comercial (experimento B) utilizando densidade de aves semelhante, de maneira a possibilitar uma validação. Foram medidas continuamente: a temperatura ambiental e a amplitude e freqüência de ruídos, do grupo de pintos alojados durante a fase de aquecimento em ambos experimentos. Houve correlação entre um padrão de comportamento de agrupamento e a vocalização, medida não somente pela amplitude do ru...

Performance of chicks subjected to thermal challenge

“…Moura et al (2008) pointed out that low t db in the first days of life may impair both bird development and health. This can be explained by the fact that chicks have a large body surface area to volume ratio, making them less effective in conserving body heat.…”

“…This is attributed to the fact that newborn chicks are poikilothermic, due to their not yet developed thermoregulatory mechanisms (Mujahid, 2010). As a result, chicks are particularly sensitive to thermal environments outside their comfort range (Moura et al, 2008;Mujahid & Furuse, 2009;Chowdhury et al, 2012). Broilers achieve the best performance when reared in thermoneutral conditions.…”

Infrared thermography applied to the evaluation of metabolic heat loss of chicks fed with different energy densities

“…The higher dietary energy level of the diet containing soybean oil resulted in lower metabolic heat production, as demonstrated by the difference between treatments in mean surface temperature of individual birds (p <0.02) and of the entire flock (p <0.01, Table 2). When evaluated separately from the flock, individual surface temperature was lower and independent of dietary energy level, suggesting that the clustering of birds allowed the reduction of radiant heat loss, (measured by the thermographic camera (Shinder et al 2007;Moura et al, 2008). 27.34 T1 = 2950kcal ME/kg, T2 = 3950kcal ME/kg.…”

Technology and Poultry Welfare

“…Thus, Moura et al [38] estimated thermal comfort and chick performance based on the analyses of amplitude vocalizations and the noise frequency spectrum (using Cool Edit ® and Audacity ® ) of broiler chicks placed under varying environmental temperatures, while collecting their behavioural response in parallel. They showed that when temperature decreased, the amplitude and frequency of the vocalizations increased as birds grouped together to reduce heat loss, while during thermal comfort the amplitude and frequency of vocalizations stabilized.…”