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United States Department of Agriculture

Agricultural Research Service

Related Topics

Research Project: Optimizing Heavy Broiler Management and Housing Environment for Sustainable Production

Location: Poultry Research

2013 Annual Report


1a.Objectives (from AD-416):
Objective 1: Characterize energy exchange between broilers and their surrounding micro-environment as influenced by thermal conditions, ventilation regimes, and dietary energy levels, with special emphasis on genetic strains for heavy market weights. Sub-objective 1.1. Determine heat and moisture production of heavy broilers for differing temperature conditions. Sub-objective 1.2. Determine heat and moisture production of heavy broilers as influenced by dietary energy levels. Sub-objective 1.3. Determine heat and moisture production of heavy broilers as influenced by light intensity. Sub-objective 1.4. Estimate convective heat loss coefficients for single and grouped birds.

Objective 2: Determine the effects of light sources, intensity and photoperiod on growth performance, welfare indices, and physiological responses in broiler chickens grown to heavy weights to ensure optimum production efficiencies, bird health, and well-being. Sub-objective 2.1. Determine the effects of light sources on growth performance, blood biochemical, and physiological variables in broiler chickens grown to heavy weights. Sub-objective 2.2. Evaluate the effects of photoperiod (long, regular, and short), light sources and their interaction on growth performance, meat quality, welfare indices, blood biochemical, and physiological variables in broiler chickens grown to heavy weights. Sub-objective 2.3. Examine the effects of light sources, photoperiod, and strain on growth performance, meat yield and selected physiological variables of broiler chickens grown to heavy weights since rate of development differs among genetic strain.

Objective 3: Assess the impact of inter-flock litter management on litter quality, bird health, and energy use during the brooding period. Sub-objective 3.1. Assess the impact of different windrowing techniques on pre-placement litter quality during the brooding period. Sub-objective 3.2. Compare the impact of windrowing vs. extended layout duration on pre-placement litter quality and energy use during the brooding period. Sub-objective 3.3. Characterize seasonal effects for common litter management techniques on pre-placement litter quality and energy usage.

Objective 4: Characterize energy efficiencies of current environmental control systems, energy use partitioning, and improve efficiencies of alternative energy recovery strategies in commercial broiler houses while optimizing internal air quality, bird health, and production efficiencies. Sub-objective 4.1. Characterize energy use and partitioning in typical commercial broiler houses and provide estimates of specific energy consumption to develop common language for reporting efficiency gains. Sub-objective 4.2. Characterize spatially referenced energy efficiency of radiant heating systems. Sub-objective 4.3. Improve efficiency of heat recovery from alternative heating systems. Sub-objective 4.4. Evaluate alternative ventilation control strategies to improve internal air quality, bird health and production efficiency.


1b.Approach (from AD-416):
Three trials will be conducted to determine heat and moisture production values for broiler chickens from 45 to 49, 52 to 56, and 59 to 63 days of age for three differing air temperature profiles. Each trial will represent two replicates of each treatment, and will be repeated over time to obtain a total of six replicates. Six environmental chambers measuring 2.4 x 2.4 m will be used for this experiment and birds will be housed at nominal commercial stocking density (10.7 birds/m2). A total of 360 birds will be used in each trial (60 birds/rep × 2 reps/trt × 3 trts = 360); 1,080 birds will be used in total over three trials. Treatments will be randomly assigned to each chamber for each trial. Three temperature profiles will be used: elevated, moderate, low. Endpoints for the temperature profiles will be 28, 21, and 15°C, respectively, and will reduce linearly from placement temperature. Chicks will be placed in an alternate facility and reared to 41 days of age. On day 42, pen weights will be equated and birds will be transported to the environmental chambers. Calorimetry measurements will commence on day 45 and continue through day 63.

Total heat production (THP) and moisture production (MP) will be measured using indirect calorimetry per procedures previously established for poultry and swine. Oxygen (O2), carbon dioxide (CO2), and water vapor concentrations will be measured at the inlet and exhaust of each environmental chamber. Gas analysis will be performed with a paramagnetic oxygen analyzer, photoacoustic infrared gas analyzer (for CO2), and a chilled mirror hygrometer (water vapor). Total heat production (THP) will then be calculated according to Brouwer (1965) as modified for poultry: THP = 16.18O2 + 5.02CO2. Oxygen and CO2 production rates will be calculated from differential concentrations of each gas and airflow rates. Moisture production rates will be calculated from differences in inlet and exhaust absolute humidities.

Gas samples will be acquired and analyzed three times per hour. Gas analysis equipment will be calibrated twice daily using primary standard calibration gases. Alcohol combustion tests will be performed prior to each experiment to verify mass recovery rates. Mass air flow will be measured using automotive mass air flow sensors calibrated against a reference instrument. Body weight will be measured weekly; feed and water consumption will be measured hourly.


3.Progress Report:
Calorimetry experiments for Objective 1.1 show at moderate temperatures (21 C) total heat production of heavy broilers ranged from 3-4.5 W/kg, indicating total heat production increased. Birds returned to normal feeding patterns after 48 hours. Heat production at lower temperatures (15°C) is being investigated. Four lighting sources were used in Objective 2.1 comparing incandescent, compact fluorescent, and a filtered light emitting diode (LED) at two differing light intensities. Results show no differences in performance or physiological response to different light sources, indicating performance is neither enhanced nor limited by the type of lighting used in the house environment under typical commercial lighting programs while energy use and initial cost are the driving factors when considering changes in lighting equipment. Objective 3.1 was not completed. Litter moisture, litter (measure of litter hydrogen ion concentration) pH, windrow temperatures, ammonia release from litter, and total microbial counts (aerobes, anaerobes, coliforms) were accomplished but polymerase chain reaction (PCR) techniques for pathogen identification are in progress while litter mineral composition and particle size were not addressed. The cooperator has indicated that pending completion of the PCR technique, Objective 3.1 will be fully completed within the following 12 months along with the 24 month milestones. Regarding progress of Objective 4.1, power and fuel monitoring equipment were installed in a commercial broiler house in Mississippi to assess whole-house energy usage for the following classes of poultry house equipment: ventilation (exhaust fans), feeding systems, heating systems, evaporative cooling systems, and lighting system. System testing shows installed ventilation capacity is less than design capacity, thus specific power usage (W/cfm) is increased when compared to fan performance tests. Also, thermal insulation values for common installation methods were assessed using a heat flux sensor array. Spray foam, fiberglass batt, and foil bubble insulation were evaluated for insulation efficiency in a commercial broiler house during the latter stages of the growout phase. Data for heating conditions will be collected on the subsequent flock. Progress on Objective 4.2 included the construction of black globe temperature arrays to develop a standard method of comparing radiant brooders. The heating patterns of natural gas fired radiant brooders were characterized using the black globe arrays as a measure of radiant heating efficiency. Differences in heating profiles are apparent among the brooders. Objective 4.3 progress includes the development of computational models to assess attic heating in two dimensional heat transfer and flow. Previous efforts to determine air temperature distribution in the attic space were used as boundary conditions for the computational model. Qualitative agreement between the model and field data was observed. Refinement of the model is necessary to evaluate attic heat flows in three dimensions. Progress on Objective 4.4 stymied due to a critical vacancy.


Last Modified: 4/20/2014
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