Characterization of Thermal Patterns Using Infrared Thermography and Thermolytic Responses of Cattle Reared in Three Different Systems during the Transition Period in the Eastern Amazon, Brazil

Abstract

In the Lower Amazon mesoregion, there are basically three types of production systems: the traditional (without shade and no bathing area), the silvopastoral (with shade and no bathing area), and the integrated (with shade and bathing area). It is considered that the type of production system influences the thermal comfort and productivity of cattle, so this research aims to evaluate the influence of these three types of production systems on the thermoregulation of Nellore cattle. The experiment was carried out on a rural property for raising cattle, located in Mojuí dos Campos, Pará, Brazil, during the transition period (June/July). Thirty bovine males (not castrated, aged between 18 and 20 months, average weight of 250 ± 36 kg, body condition score of 3.5, clinically healthy) were randomly divided into three groups: Silvopastoral System—SS (n = 10), Traditional System—TS (n = 10), and Integrated System—IS (n = 10). Climate variables were collected (air temperature (AT °C), relative humidity (RH %), wind speed (WS, m/s), solar radiation (SR), black globe temperature (BGT °C), and physiological parameters, such as respiratory rate (RR) and rectal temperature (RT)) at 6 a.m., 12 p.m., 6 p.m., and 12 a.m. to determine the thermal comfort situation of the animals. Thermographic images of the environment and animals were captured in order to obtain the body surface temperature (BST) through infrared thermography. The Benezra Thermal Comfort Index (BTCI), Environmental Stress Index (ESI), Equivalent Temperature Index (ETI), and Iberian Heat Tolerance Index (Iberian HTI) were used. The results showed that the silvopastoral system, with shading by chestnut trees and an ample vegetative area, presented better thermal conditions, with an average of 28.98 °C, in comparison with the traditional system (35.93 °C) and the integrated one (34.11 °C). It was observed that the body surface temperature of cattle did not differ significantly between the anatomical regions of the body and the studied systems (p > 0.05). As for the respiratory rate, the traditional system registered higher values, with an average of 41 movements per minute, indicating possible thermal stress (p < 0.05). The thermal comfort indices revealed that all systems presented moderate stress conditions during times of higher solar intensity. It is concluded that the silvopastoral system proved to be more favorable for cattle, providing shade and reducing thermal stress, which may have a positive impact on animal welfare and productivity in this region.

Thermal Comfort of Nelore Cattle (Bos indicus) Managed in Silvopastoral and Traditional Systems Associated with Rumination in a Humid Tropical Environment in the Eastern Amazon, Brazil

“…The increase in temperature during the period from 10:00 a.m. to 6:00 p.m. is consistent with the increase in direct solar radiation during the daylight hours, which culminates in its peak at 4:00 p.m. The high temperature observed at 16:00 (40 • C) is a reflection of the increase in solar radiation and heat accumulation throughout the day, and the relative humidity is higher during the night [18].…”

Thermographic Profiles in Livestock Systems under Full Sun and Shaded Pastures during an Extreme Climate Event in the Eastern Amazon, Brazil: El Niño of 2023

“…In general, animals look for areas with the presence of shadows during times of greater incidence of solar radiation since they are more susceptible to heat stress. The implementation of trees in pastures has become a sustainable option [ 90 ], due to improved welfare for livestock in tropical regions [ 28 , 50 , 91 ].…”

“…The thermograms were then examined using Flir Tools software, version 6.3, with the Rainbow HC palette chosen. The operator used the camera at eye level, always maintaining consistency and without the aid of a tripod, focusing perpendicular to the target, following the methodological guidelines proposed by Barreto et al [ 49 ] and Silva et al [ 50 ].…”

The Challenge of Global Warming in Water Buffalo Farming: Physiological and Behavioral Aspects and Strategies to Face Heat Stress

“…assesses the surface temperature of the skin as the vasomotor response of the organism to dissipate or conserve heat depending on the thermal state of the animals (i.e., hyperthermia or hypothermia) [95]. Currently, IRT is being applied in veterinary medicine as a real-time method to evaluate hemodynamic changes and the thermostability of animals due to thermal stress, inflammatory processes, pain, stressor exposure, and during different conditions and events (e.g., newborns or during transport) in a wide variety of species [14,55,[95][96][97][98][99].…”