Spatial modeling via geostatistics and infrared thermography of the skin temperature of dairy cows in a compost barn system in the Brazilian semiarid region

Abstract

The aim of the study was i) to determine the spatial variability of the skin temperature of dairy cows in a compost system and ii) to evaluate the thermal comfort conditions of confined animals. Skin temperature (Tskin,°C) was recorded in three animals at 9:00 am (morning) and the measurement was repeated at 3:00 pm (afternoon) using a thermographic camera (model FLIR i60). Tskin data were submitted to descriptive statistics, geostatistics, and later elaborated kriging maps. When comparing the Tskin mean at 9:00 am and 3:00 pm, for animal 3, there was a reduction of 0.30°C in the afternoon shift, as a result of the individual's position concerning the forced ventilation system. The use of the geostatistics technique made it possible to verify the occurrence of a strong spatial dependence between the skin temperatures of cows raised inside a facility with a compost barn system, with the Gaussian model showing the best fit of the data (R2>0.90), for the morning and afternoon recording shifts. The characterization of the spatial variability of the Tskin of dairy cows allowed us to identify the comfort conditions of the animals housed in the compost barn systems.