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Thermoregulatory responses of day-old chickens submitted to simulated transport condition: effect of exposure time under different thermal ranges

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan

Citation:  2012 IX International Livestock Environment Symposium (ILES IX)  ILES12-2234.(doi:10.13031/2013.41608)
Authors:   Frederico M C Vieira, Iran J O Silva, Késia O Silva-Miranda, Aérica C Nazareno, Juliano R Camargo, Afrânio M C Vieira
Keywords:   logistics, day-old chickens, stress, welfare

In this study, we assessed the thermoregulatory responses of day-old chickens exposed to different dry-bulb temperature and relative humidity ranges and varying exposure times, under simulated condition of transport. In this experiment, Cobb 500 1-day-old chicks (n = 900), were exposed to a thermoneutral (35C; relative humidity 60%), cold stress (20C; 75%) and heat stress (38C; 75%) treatments during three time intervals (0, 3 and 6 hours), in a climatic chamber. Those animals were obtained from a commercial hatchery, from selected eggs which were stored and incubated in the same conditions. Female broiler breeders were about 41 weeks old. The animals were placed in boxes (n=3) for day-old chicks transport, divided in 100 chicks per box, and each box was intercalated with empty boxes, all stacked vertically, for each thermal treatment. Body weight, respiratory rate, body surface temperature, mortality rate and cloacal temperature were monitored in a sample of 5 animals per box after the time interval treatment. The thermal profile inside the climatic chamber was monitored through temperature, relative humidity and specific enthalpy. A completely randomized design was adopted and the treatment structure was a 3 x3 factorial design (3 thermal ranges and 3 time intervals). Data were analysed by ANOVA and means differing significantly were separated by the Tukeys test procedure. It can be concluded that the heat stress during day-old chicks was the most stressful condition, considering physiological and mortality responses. Also, these responses were more aggravated after 3 hours of exposition to harsh environmental conditions.

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