Modelling of Animal Activity, Illuminance, and Noise on a Weaned Piglet Farm

SIMPLE SUMMARY: Measuring animal activity and its evolution in real time is one way of assessing animal welfare. Passive infrared sensors are a low-cost solution used in weaned piglet farming that has correlated well with human observation. In addition, using other easily measured variables that provide data about animal activity in the building, such as illuminance or noise level, is also relevant. This paper establishes relationships between animal activity as measured by passive infrared sensors, illuminance and noise levels on a conventional weaned piglet farm. Fitting a cosine model to three harmonics of animal activity has proven effective in modelling these three variables. Noise level and illuminance are easily measured variables that can provide reliable information about animal activity by implementing only one sensor, a sonometer or a lux meter. Unlike passive infrared sensors, sonometers and lux meters are not affected by the physical barriers that divide the farm. ABSTRACT: Measuring animal activity and its evolution in real time is useful for animal welfare assessment. In addition, illuminance and noise level are two factors that can improve our understanding of animal activity. This study aims to establish relationships between animal activity as measured by passive infrared sensors, and both illuminance and noise level on a conventional weaned piglet farm. First, regression models were applied, and then cosine models with three harmonics were developed using least squares with a Generalized Reduced Gradient Nonlinear method. Finally, all the models were validated. Linear models showed positive correlations, with values between 0.40 and 0.56. Cosine models drew clear patterns of daily animal activity, illuminance and noise level with two peaks, one in the morning and one in the afternoon, coinciding with human activity inside the building, with a preference for inactivity at night-time and around midday. Cosine model fitting revealed strong correlations, both in the measurement and validation periods, for animal activity (R = 0.97 and 0.92), illuminance (R = 0.95 and 0.91) and noise level (R = 0.99 and 0.92). The developed models could be easily implemented in animal welfare monitoring systems and could provide useful information about animal activity through continuous monitoring of illuminance or noise levels.