Joseph L. Purswell

Effect of Temperature-Humidity Index on Live Performance in Broiler Chickens Grown From 49 To 63 Days of Age

The thermal environment in poultry housing is a primary influence on production efficiency and live performance. Heavy broilers (body weight > 3.2 kg) typically require high ventilation rates to maintain thermal comfort and production efficiency. However, large birds are observed to pant in mild to moderate thermal conditions, indicating that upper critical temperatures may be lower at larger body weights. Thermal comfort indices such as the temperature-humidity index (THI) integrate the effects of temperature and humidity and may offer a means to predict the effects of thermal conditions on performance. The objective of this study was to determine live performance of heavy broilers over a range of dry-bulb temperature (15°C, 21°C, and 27°C) and relative humidity (50%, 65%, and 80%), hence THI (14.8°C to 26.9°C). A series of four studies were completed with broiler chickens housed in environmental chambers. Live performance parameters including body weight, body weight gain, feed intake, and feed conversion ratio were compared; body temperature was measured in three birds of each treatment during one study. Results show that as THI exceeds approximately 21°C, bird performance significantly declined and body temperature increased up to 1.7°C above nominal body temperature for broilers (41°C). Regression analysis showed that a quadratic relationship exists between THI and the four performance parameters of interest. Prediction accuracy was decreased due to variability in the data and suggests data at additional THI points are necessary.

Effects of color temperatures (kelvin) of LED bulbs on growth performance, carcass characteristics, and ocular development indices of broilers grown to heavy weights

Limited data are available for comparing light-emitting diode (LED) bulbs that are currently available in commercial broiler production facilities. We evaluated the effects of color temperatures (kelvin) of LED bulbs on growth performance, carcass characteristics, and ocular development indices of broilers grown to heavy weights (>3.0 kg). The experiment had a randomized complete block design. Four treatments consisted of 3 LED light bulbs (2,700 [warm LED]; 5,000 [cool LED 1]; and 5,000 K [cool LED 2]) and incandescent light (2,010 K [ICD], standard) from day zero to 56 d of age. A total of 960 Ross×Ross 708 day-old chicks were equally and randomly distributed into 16 environmentally controlled rooms at 50% RH (30 males and 30 females/room). Thus, each of the 4 treatments was represented by 4 rooms (4 replicates) per trial. Feed and water were provided ad libitum. All birds were fed the same diet. Ocular specimens were collected on d 42 for development and histopathologic examination. Blood samples were collected on d 21, 28, 42, and 56 to determine plasma corticosterone. On d 56, twenty birds from each room (10 males and 10 females) were processed to determine weights and yields. The BW and BW gain (BWG), live weight, and carcass weights of birds reared under cool LED 1 were different in comparison to birds reared under ICD (P<0.05). However, feed intake (FI), feed conversion ratio (FCR), and mortality were not affected by treatments. The treatments did not affect fat, breast and tender weights, and yields. In addition, ocular development indices and plasma corticosterone concentrations were not affected by treatments, suggesting the LED light bulbs we evaluated did not compromise the welfare of the birds. It was concluded that cool LED 1 may be a better potential replacement light source in comparison to ICD on performance, but it may be equal when compared to other LED light sources examined in this study.

THERMAL ENVIRONMENT IN A FOUR-HORSE SLANT LOAD TRAILER

Little information has been published describing thermal conditions in horse trailers while in transit. Dry bulb temperature (Tdb), globe temperature (Tg), and relative humidity (RH) were measured in ten locations within a fully enclosed four-horse slant-load trailer with and without animals to assess the thermal environment during transport as influenced by vehicle speed and vent configuration. Wet bulb globe temperature (WBGT) was calculated to assess thermal comfort. Interior-exterior temperature differences were analyzed to account for effects of changing weather conditions. Temperature differences between the interior of the trailer and ambient conditions for Tdb ranged from 5.1°C to 9.5°C, dew point (Tdp) ranged from 4.4°C to 13°C, and WBGT ranged from 2.9°C to 7.9°C. Temperature differences decreased with increasing vehicle speed and open vent area and increased with animals present. Heat stress conditions are likely to occur in horse trailers of similar design given their limited ventilation and the temperature increases measured in this study, and warrant improvements in trailer design to increase ventilation.

AIR EXCHANGE RATE IN A HORSE TRAILER DURING ROAD TRANSPORT

Horses traveling by road commonly experience heat stress conditions and poor air quality, which may be caused by insufficient ventilation; however, there are few estimates of air exchange in a horse trailer during transport. Air exchange rate was measured at ten locations within a four-horse trailer (internal volume 18.5 m3) using tracer gas decay measurement to assess the adequacy of ventilation. Three vehicle speeds (13, 48, and 97 km h-1) and three window configurations (all windows and roof vents closed, all windows open, all windows open and roof vents open forward) were tested with and without animals present in the trailer. External air temperature ranged from 22.3°C to 28.3°C with an average of 25.3°C, and internal air temperature ranged from 29.9°C to 34.8°C with an average of 31.3°C with animals present. Air exchange rate increased with vehicle speed and open window and vent area. The average air exchange rate over all vehicle speeds and ventilation configurations was 0.52 min-1 with animals present and 0.76 min-1 without animals. Without animals present, the maximum mean exchange rate was 1.42 min-1 at 97 km h-1 at the rear left window with all windows and vents open; the lowest mean exchange rate was 0.12 min-1 at 13 km h-1 with all windows and vents closed at the lower position of the rearmost stall divider. With animals present, the maximum air exchange rate observed was 0.84 min-1 with all windows and vents open and traveling at 97 km h-1. Ventilation in the trailer was not adequate when compared to recommendations for stabled horses for any combination of vehicle speed or ventilation configuration. Increasing open vent area, either by increasing the number and size of roof vents or the size of windows in the sidewall, would be the most cost-effective means of increasing air exchange in a horse trailer.

Methods of Remote, Continuous Temperature Detection in Beef Cattle

Beef cattle core body temperature (CBT) was remotely and continuously measured over three ambient conditions (Period 1 at 30 °C, Period 2 at 20 °C, and Period 3 at 15 °C) at three sites: rectum, near the tympanic membrane, and peritoneal cavity. Ear surface measurements were taken under the same conditions with a temperature sensor placed on the ventral ear surface and were compared to the CBT measurements. Visual observation of the temperature measurements illustrated similar trends in the ear surface temperature and CBT measurements over time. A differencing method was used create a Temperature Index to detect the onset of fever in cattle. The use of the Index as a threshold showed promise. The animals’ baseline temperatures (Periods 1, 2 and 3) did not intersect this threshold until fever was present. A different threshold value was determined for rectal vs. ear surface temperatures. While promising, this system of detection needs improvements in hardware reliability and convenience before it can be implemented into a production setting.

Moisture Determination in Windrowed Switchgrass Using Electrical Resistance Probes

Determining moisture content (MC) levels in windrowed biomass is important for both forage producers and researchers. Energy crops such as switchgrass have been troublesome when using standard methods set for electrical resistance meters. The objectives of this study were to i) develop the methodologies needed to measure MC in switchgrass using electrical resistance meters, ii) to determine the effects of pressure and probe orientation on MC measurement and iii) to generate MC calibration equations for electrical resistance meters using switchgrass in the senescence growth stage. Two meters (Meter 1, Farmex HT-PRO; Meter 2, Delmhorst F-2000) were selected based on commercial availability. A forage compression apparatus was designed and constructed with on-farm materials and methods to provide a simple system of applying pressure achievable by any forage producer or researcher in the field. A study was performed to test four levels of moisture contents (10%, 20%, 30%, and 40%), five pressures (0, 1.68, 3.11, 4.55,

Temporal variability of illuminance in commercial broiler houses

Abstract. Lighting is an essential management tool in poultry production and influences production efficiency through physiological and behavioral responses. Lighting programs for commercial broilers have traditionally prescribed photoperiod and illuminance (intensity). Lighting programs are often tailored by integrators to meet performance goals and minimize adverse behaviors. Ingress of ambient light through ventilation system components can override the prescribed lighting program and has been shown to negatively affect production efficiency. The objective of this study was to characterize temporal variation of illuminance in a commercial broiler house. Illuminance was measured over a six-day period in a tunnel ventilated commercial broiler house in Mississippi using a network of photometric sensors. Three locations were measured along the length of the house: near evaporative pad inlets, mid-house, and near the tunnel fans; sensors were alternately placed near the sidewall (days 1, 3, and 5) and the center-line of the house (days 2, 4, and 6). Results indicate that both illuminance and temporal variability of illuminance were greatest near the tunnel fans as expected. Mean illuminance for the photoperiod was 0.95 and 12.22 lux, for the mid-house and fan locations, respectively and exceeded the target setpoint of 0.5 lux when the lighting system or fans were operating during daylight hours. Temporal variation, as measured by CV, ranged up to 129% at the mid-house location. Given that light ingress increases feed intake and feed conversion, improved control over the light environment in commercial broiler houses can enhance the utility and effectiveness of lighting programs.

Automatic Identification of Broiler Mortality Using Image Processing Technology

Abstract. Identifying dead birds is a time and labor consuming task in commercial broiler production. Automatic mortality identification not only helps to save the time and labor, but also offers a critical procedure/component for autonomous mortality removal systems. The objectives of this study were to 1) investigate the accuracy of automatically identifying dead broilers at two stocking densities through processing thermal and visible images, and 2) delineate the dynamic body surface temperature drops after euthanasia. The tests were conducted on a weekly basis over two 9-week production cycles in a commercial broiler house. A 0.8mx0.6m floor area was fenced using chicken wires to accommodate experimental broilers. A dual-function camera was installed above the fenced area and simultaneously took thermal and visible videos of the broilers for 20 min at each stocking density. An algorithm was developed to extract pixels of live broilers in thermal images and pixels of all (live and dead) broilers in visible images. The algorithm further detected pixels of dead birds by subtracting the two processed thermal and visible images taken at the same time, and reported the coordinates of the dead broilers. The results show that the accuracy of mortality identification was 90.7% for the regular stocking density and 95.0% for the low stocking density, respectively, for 5-week old or younger broilers. The accuracy decreased for older broilers due to less body-background temperature gradients and more body interactions among birds. The body surface temperatures dropped more slowly for older broilers than younger ones. Body surface temperature requires approximately 1.7 hour for 1-week old broiler to reach 1°C above the background level, while over 6 hours for 4-week and 7-week old broilers. In conclusion, the system and algorithm developed in this study successfully identified broiler mortalities at promising accuracies for younger birds (

Assessing Cross-Sectional Air Velocity Uniformity in Commercial Broiler Houses via the Traverse Method

Abstract. Air velocity is a contributing factor to maintaining a production environment that promotes production efficiency, thermal comfort, and animal well-being. Variations in size, design, and equipment of production facilities contribute greatly to the air velocity generated. This study assessed mean cross-sectional air velocities and total air flow of two broiler production facilities. Test facility 1 was an 18.3 A— 170.7 m smooth sidewall broiler production facility and test facility 2 was a 12.19 A— 121.9 m curtain sidewall broiler production facility. Air velocity was characterized down each house with a Scalable Environment Assessment System (SEAS). Cross-sections were measured at 2.44 m and 3.05 m intervals in the axial direction for test facility 1 and 2 respectively. Total air flow was measured with Fan Assessment and Numeration System (FANS) units. Normalized cross-sectional air velocity was plotted against proportion of total house length to compare the cross-sectional air velocity of the two facilities. Test facility 1 showed 26.5% of the total house length below superficial velocity while test facility 2 only had 17.5% below superficial velocity. Test facility 1 demonstrated 11.4% of the facility length below normalized superficial velocity for temperature control at the exhaust fan end of the facility. Physical arrangement of the feed hoppers, heating systems, and tunnel fans are important for improving uniformity of air velocity in commercial broiler houses.

Improving Commercial Broiler Attic Inlet Ventilation through CFD Analysis

The use of solar heated attic air is an area of increasing interest in commercial poultry production. Attic inlets satisfy the demand for alternative heating while being simple to implement in an existing poultry house. A number of demonstration projects have suggested that attic inlets may decrease the amount of fuel required to raise minimum ventilation air to set point temperature by tempering the inlet air. However, little attention has been given to the configuration of the attic space and its influence on thermal energy extraction. The objectives of this study were as follows: 1) Collect data for the operation of attic inlets in a commercial broiler house, 2) develop a two-dimensional computational fluid dynamic (CFD) simulation model using experimental data, and 3) Use the simulation to investigate the efficiency of attic inlet system configurations. Field data collected during the operation of attic inlets in an east-west oriented broiler house illustrated the asymmetric heating and stratification of air temperature. A two dimensional CFD simulation model was developed for attic inlet system operation using field data to develop boundary conditions. The simulation demonstrated that the strategic placement of a simple 2.44 m ridge cap diverter and a central inlet riser (1.3 m high) may increase thermal energy extraction by 55% and 68% (30 s and 60 s fan runtimes, respectively) over the measured attic inlet system.