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Construction and Performance of a Self-Contained, Temperature-Controlled Heat Source to Quantify Thermal Load during Live Haul of Broilers

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

Citation:  10th International Livestock Environment Symposium (ILES X)  .(doi:10.13031/iles.18-006)
Authors:   Kaushik Luthra, Yi Liang, James R Andress, Thomas A Costello, Susan E Watkins
Keywords:   Broiler transport, Physiological stress, Thermal micro-environment, Thermoneutral zone


Strategies for quantifying heat loss of broilers on live-haul trailers would be beneficial, particularly under conditions of environmental extremes. We have developed an electronic chicken (a self-contained, temperature-controlled heat source) to simulate the sensible heat loss of a live broiler in commercial live-haul trips. The simulated electronic chicken is an aluminum box, having surface area equivalent to a 2.3 – 2.8 kg broiler chicken (0.13 m2), with a thermostatically controlled power source to maintain the internal temperature at 41°C. Different cover materials were tested in order to match measured heat production of electronic chicken with published values of sensible heat production for broilers. A double layer of fleece fabric provided a reasonable match. The sensible heat loss of the electronic chickens exhibited positive correlation with exposed wind and a positive correlation with temperature gradient between internal and external environment. Wetting the fabric cover of electronic chickens only slightly increased heat loss as compared to the dry fabric cover, therefore heat loss under the wet scenario could be underestimated. Electronic chickens were installed in modules on trailers with live chickens during commercial live-haul process under various environmental conditions and different management practices. Measured heat losses from electronic chickens were in the range of 8.2 to 20.3 W with outside temperature of -17°C to 3.0°C in winter, and 4.5 to 6.7 W with 28°C to 34°C in summer. Based on literature-reported sensible heat loss under thermoneutrality, it was determined that the measured air temperature inside the live-haul modules on the trailer in the range of 11°C - 25.1°C during transit (outdoor temperature range of 1.7°C – 22.2°C) and 5.3°C-21.7°C during holding (outdoor temperature range of -9.1°C – 19.8°C) would allow the live chickens to regulate heat by their metabolism and stay comfortable. For the holding period, the winter trips were mostly in the zone of thermal comfort. In summers, hyperthermic conditions likely existed during transit, although additional cooling due to surface wetting of birds (on the farm prior to beginning the transit) may have been beneficial but not detectable by electronic chickens. The electronic chickens can be used effectively as a model to evaluate and identify conditions that cause thermal stress conditions during live-haul conditions and to design systems and strategies to alleviate that stress.

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