Modeling of Ambient Environment and Thermal Status Relationship of Pig’s Body in a Pig Barn

Abstract

An experiment was conducted to evaluate the performance of temperature model (T model), relative humidity model (H model), temperature-humidity model (TH model), and temperature-humidity index model (THI model) in predicting pig’s body surface temperature (PBT). Infrared Sensor (IR) was used to measure PBT at different locations: left side (LS), right side (RS), forehead (FH) and back side (BS). Ambient environmental parameters inside the room such as temperature (ART), relative humidity (RRH) and CO2 concentration were measured using livestock environment management system (LEMS). THI model was selected as the best model in making more accurate prediction in both training (R2=0.72, RMSE=0.80, RSE=0.26 and MAPE=2.08) and validation (R2=0.74, RMSE=1.10, RSE=0.40 and MAPE=2.80) stages. For more precise modeling, apart from temperature and humidity data other environmental factors inside pig’s barn (CO2 concentration, wind speed, air pressure etc.) as well as growth factors (body weight, feed intake etc.) may be included in models.

Systematic review of animal-based indicators to measure thermal, social, and immune-related stress in pigs

“…The environmental variables are as follows: temperature (T) and relative humidity (RH). THI is calculated using the equation defined by the National Research Council (NRC) in 1971 [ 66 ], where T is the maximum daily temperature in degrees Celsius, and RH is the minimum daily humidity ranging from 0 to 100 [ 44 , 63 , 64 , 66 ].…”

“…Thermal stress is generated by a combination of environmental factors, such as humidity and ambient temperature, and the anatomical fact that pigs have a decreased perspiration capacity [ 6 , 45 , 70 – 72 ]. Therefore, environmental indices and mathematical models have been developed to estimate the impact of the rise in environmental temperature on the thermal status of animals [ 43 – 46 , 64 , 65 , 73 , 74 ]. In particular, the increase in the indices measured in the studies relative to the thermoneutral conditions of each study were reported in each study.…”

“…In particular, the increase in the indices measured in the studies relative to the thermoneutral conditions of each study were reported in each study. Among the literature reviewed, the temperature-humidity index (THI) has been the most widely used model for predicting pig body temperature, based on environmental temperature and humidity [ 64 ]. Environmental indices, such as the black globe temperature index, humidity index, THI, thermal circulation index, and heat load, generate differences in the indices results relative to the animal-based measurements (rectal or skin temperature), due to variations in factors such as wind speed, air pressure, body weight, and feed intake.…”

Machine Learning-Based Microclimate Model for Indoor Air Temperature and Relative Humidity Prediction in a Swine Building

“…These models are also popular among the fields such as weather prediction, electricity load, energy consumption, heat transfer, business forecast, etc. [ 25 , 26 , 27 , 28 ]. Generally, regression models examine the relative influence of the independent variables or predictor variables on the dependent variables or response variables.…”

“…MLR models are popular among the forecast because of their non-complex structures, calculation interpretability, and the ability to identify outliers or anomalies in given predictor variables. An MLR model can be expressed by the following equation [ 25 , 26 , 27 , 28 ], where Y is the response (output) variable; X is the predictor (independent) variable (from X 1 to X i ); a is the regression coefficient to predict Y (from a 1 to a i ); a 0 is the intercept/constant of the model; and the Ɛ is the noise or random error of the model.…”