Performance of chicks subjected to thermal challenge

Abstract

-The objective of this work was to evaluate the effect of thermal challenge at different intensities and durations on the production responses of 3 to 21-day-old broiler chickens. Two hundred and ten Cobb chicks were subjected to dry-bulb temperatures (t db ) of 27, 30, 33, or 36°C for the duration of 0, 1, 2, 3, or 4 days from the second day of life onwards. The experiment was carried out in four identical environmentallycontrolled wind tunnels. Data on body mass (BM), feed intake (FI), and water intake (WI), all in grams, were monitored daily; and body weight gain (BWG), in grams, and feed conversion (FC) were also calculated. The effect of duration was not statistically significant. Empirical models were adjusted to relate BM, FI, and WI with t db and bird age. The performance of chicks at 21 days of age was analyzed using the BM, FI, WI, BWG, and FC values. Overall, the development of chicks at 33 and 36°C was better than that of those subjected to the lower t db of 30 and 27°C. The exposure of chicks to cold thermal challenge in early life can have a carry-over negative effect on their production performance up to 21 days of age.Index terms: air temperature, broiler, carry-over effect, production responses, thermal stress. Desempenho de pintinhos submetidos a estresse térmicoResumo -O objetivo deste trabalho foi avaliar o efeito do estresse térmico em diferentes intensidades e durações sobre as respostas produtivas de frangos de corte de 3 a 21 dias de idade. Duzentos e dez pintinhos Cobb foram submetidos às temperaturas do bulbo seco (t bs ) de 27, 30, 33 ou 36°C durante 0, 1, 2, 3 ou 4 dias, a partir do segundo dia de vida. O experimento foi conduzido em quatro túneis de vento climatizados idênticos. Dados de massa corporal (MC), consumo de ração (CR) e consumo de água (CAg), todos em gramas, foram coletados diariamente; e ganho de massa corporal (GMC), em gramas, e conversão alimentar (CA) também foram calculados. O efeito da duração não foi estatisticamente significativo. Modelos empíricos foram ajustados para estimar MC, CR e CAg em função da t bs e da idade das aves. O desempenho dos pintinhos aos 21 dias de idade foi analisado a partir dos valores de MC, CR, CAg, GMC e CA. Em geral, o desenvolvimento de pintinhos a 33 e 36°C foi melhor que o dos submetidos às menores t bs , de 30 e 27°C. A exposição de pintos de corte ao frio nos primeiros dias de vida pode causar efeito residual em suas respostas produtivas até 21 dias de idade.Termos para indexação: temperatura do ar, frango, efeito residual, respostas produtivas, estresse térmico.

Decision Trees for Predicting the Physiological Responses of Rabbits

“…When t db is below the TNZ, a negative influence is exerted on the animals. Similar to findings for other animals, in cold challenge conditions, part of the animal’s feed energy intake that could be used for growth or production is diverted to thermoregulation to maintain homeostasis [37]. For a severely low t db , animals can experience hypothermia, decreased alertness, and behavioural and physiological disorders [38].…”

Interaction between a Cyclically Heated Building and the Ground, for Selected Locations in Europe

“…Stress associated with an unfavorable thermal environment in the early development of broiler chickens has a very negative impact through physiological mechanisms. The first weeks of life of broilers are the most critical, and the errors made in this phase cannot be corrected in a satisfactory way in the future, which may affect final production efficiency [27,28]. The assessment of the internal environment is necessary to explain its negative impact on the production of broilers.…”

Artificial Neural Networks for Prediction of Physiological and Productive Variables of Broilers

“…In the second week, a difference between treatments was established by the intensity and duration of thermal stress. The stress intensities were 24, 27, and, 33ºC for each stage, in addition to 30ºC for tdb, which was considered as comfort for the second week of life (Cassuce et al, 2013;Ferraz et al, 2017).…”