Study On Heat And Moisture Production Of Broilers In Housing

Heat and moisture production(HP and MP)of broilers has great effect on the inside environment of the house, which is very important on ventilation system design and equipment selection of environmental control system. However systemic research on HP and MP of broilers can rarely be found in China at present. Data from other countries, which is often used for housing design in China, was mainly obtained from the experiments conducted in test chambers or under different production conditions. The climate and feeding conditions vary greatly between China and other countries, therefore it is necessary to study HP and MP of broiler under domestic weather and feeding condition so as to provide foundational information for the environmental control standard and designing criteria.Based on the research methods of other countries, a practical house without broiler was firstly used as a contrasting house for researching the heat and moisture production. The experiments were carried out in three broiler testing rooms with the completely same constructions and inside facilities.in Chinese National Poultry Testing Center. The two groups of the testing bird were also managed in the same way. Environmental factors inside and outside the testing rooms together with important production indexes were monitored, and HP, MP of broilers were calculated through inner heat-moisture balance models of different growing stages, meanwhile the relationships between HP and MP characteristics and broiler weight, environmental temperature, relative humidity were analyzed.The results show that during the whole growing period inside temperature can be promoted 0.8~ 0.9 ℃ higher by the heat production of the broilers when the outside temperature was between 12~36 ℃ and the animal density was 7 birds per m2 in the testing rooms. The heat production relatively decreased as the body mass increased. Total heat production of broilers (THP) decreased from 14.8W/kg to 8.8W/kg while the body mass increased from 0.04kg to 2kg, and sensible heat production (SHP) decreased from 9.3 W/kg to 2.7W/kg. THP varied during different growing stages and the ratio of SHP and LHP (latent heat production) also changed. Within proper temperature ranges no significant difference of the heat production per body mass unit was found, however it decreased as temperature increased when the environmental temperature was above 22 ℃. Within the environmental temperature of 12~36℃, THP and SHP decreased as temperature increased, and the higher of the temperature was the larger of the LHP was. Considering the influence of body mass or temperature, THP and SHP and LHP were higher than the value only considering body mass or temperature, and the regression was also much better.Finally the results of heat and moisture production were compared with values from ASAE and CIGR standards, and the reason for lower value was also analyzed. Suggestions of adjusting some of the parameters are given in the paper under different production and environment conditions in order to make the design more reasonable.