Engineering solutions to address several current livestock and poultry housing challenges

Robust and sustainable controlled environment agriculture is critical to achieve optimal animal production efficiency with the least impacts to animal welfare and our environment. Achieving optimal agricultural environment is a consistent challenge for current livestock and poultry industries. Example challenges include: 1) high pre-weaning mortality of neonatal piglets in typical farrowing swine facilities, 2) maintaining egg production and sufficient well-being for laying hens under heat stress events, and 3) compromised air quality issues in most poultry housing systems. My research seeks to provide engineering solutions to address these three challenges currently faced by the animal production industry. This dissertation details research findings for projects specifically addressing these three challenges. In the U.S., pre-weaning mortality ranges from about 9 - 15% of live-born piglets. Hypothermia and low vitality are believed to be among the leading causes of pre-weaning piglet mortality. To identify neonatal piglets that are prone to hypothermia, a mathematical model was developed to predict neonatal piglet rectal temperature using surface temperatures. Time series rectal temperatures (RT), thermal images, and corresponding farrowing room conditions were recorded for a group of 99 neonatal piglets. Results showed that RT of the piglets dropped immediately after birth, with a mean drop of 4.4°C recorded in the first 15 min. Piglets experienced the lowest RT at 30 min after birth, reaching a mean low temperature of 33.6°C, approximately 5°C below birth temperature. Linear regression models were developed and assessed, with the refined linear regression model providing a more reliable prediction of piglet RT. The refined regression model presented can be used to provide a direct prediction of RT from simple measurement of the piglet ear surface temperature, with an uncertainty of about 1°C, and thus can be used as a convenient prediction tool for rapid estimation of piglet RT under typical farrowing conditions. Alternative cooling methods, especially a cooled perch system, present an intriguing opportunity for heat removal from birds under heat stress. A perch system was designed and used to examine the effects of water-cooled perches as a cooling alternative on hen performance, production, health and welfare on caged White Leghorn hens exposed to heat stress. The cooled perch system consisted of two replicates of three-tier cage units with galvanized perch pipes forming a complete loop in each tier in which cooled water circulated. Flow for each loop was provided by loop pumps that drew chilled water from an open thermal storage and returned it to the same manifold. Each thermal storage was cooled by continuously circulating water through a water chiller. Each loop pump was thermostatically controlled based on cage air temperature. The performance of the cooled perch system was assessed for a stable system operation period by analyzing the water flowrate, characterizing the loop water temperature rise profile, and using this information to establish estimates of the system total heat gain. It was noted that the circulation pump performance decreased over time, and there was a discrepancy between the pumps’ actual output and that provided by the manufacturer. Different loops and CP replicates did not have equal performance regarding loop water temperature rise and loop net heat gains. There was a strong correlation between room temperature and perch heat gain, indicating natural convection from ambient air to perch surface was the major contributor to heat gain over other heat transfer mechanisms including hen conduction. Design criteria useful for future applications of cooled perch were provided. An average daily heat gain of about 128 W/m perch length or 43.2 W/hen housed was estimated, based on 12-h day/12-h night air temperature of 35/28C and an average loop inlet water temperature of 20C. A peak-day system heat load of 64.4 kWh was estimated and required a thermal storage capacity of 2.5 kWh. Information regarding hens’ perching behavior, footpad area estimation, and thermal conductance or resistance of the footpad were provided. The U.S. egg industry faces growing pressure from consumers and retailers to transition egg production from conventional caged systems to alternative housings such as “cage-free” aviaries and enrichable caged systems, despite research that has established that alternative housing has more challenges to maintain desired indoor air quality parameters. Given the current limited knowledge regarding the interior environment in such housings, it is important to evaluate the thermal environment and air quality in order to provide additional scientific information for alternative hen houses. Indoor air temperature, RH, CO2 and NH3 concentrations were continuously monitored using the six intelligent Portable Monitoring Unit (iPMUs) for three different laying hen houses, including two aviaries and an enrichable cage house from February to July 2019. The thermal environment and the gas concentrations during the study were not uniformly distributed spatially in the houses. There was a variation in temperature distribution between the top and the bottom levels for all three houses. Hens in all three houses experienced THI conditions from normal to emergency (hot and cold) categories. The average CO2 and NH3 concentrations for the three hen houses ranged from approximately 400 to 5800 ppm and 0 to 94 ppm, respectively. During monitoring, 75% of the measurements in the three houses were lower than 5,000 ppm for CO2 and below 60 ppm for NH3 concentrations. Both winter minimum ventilation and summer tunnel ventilation were not sufficient during some monitoring periods, and further improvement to the ventilation management strategies would be helpful. Management practices to monitor the interior thermal environment, investigate the air inlets performance (number of inlets and air velocity), adjust operational static pressure (which drives the air inlets), or which fans to operate during coldest conditions, should be considered by the producer