Microclimate Optimization in Semi-Intensive Livestock Housing Using Natural Ventilation and Structural Modifications

Abstract

The thermal stress and lack of ventilation of livestock housing, as well as the fluctuating humidity levels, are a common characteristic of livestock housing in tropical areas and in semi-arid regions, which influence animal welfare, health, and productivity adversely. The use of microclimate conditions towards sustainable livestock management is hence crucial in semi-intensive production systems of cattle and sheep that are commonly used in the sector. This paper explores how natural ventilation improvement and low-cost structural changes can help in the improvement of the indoor environment conditions in the current livestock housing units. The main solutions involved installation of constant ridge ventilation to facilitate escaping of air vertically, expansion of sidewall openings to encourage rising of air horizontally, using flexible shading screens to lower the radiant heating load on the building and use of reflective roofing materials to reduce the amount of heat taken in by the sun. The environmental parameters, such as temperatures, relative humidity, air speed and Temperature-Humidity Index (THI) were monitored and compared in modified and conventional housing units. At the same time, physiological measures of the animals such as rectal temperature, respiratory speed and the panting score were checked in order to determine thermal comfort. The altered architectures were with a consistent 35C lowering of the indoor temperatures, and a 1.21.8 m/s growth of the air circulation, and a significant decrease in the indicators of the heat-stress with the animals showing lower panting levels and stable body temperatures. These findings substantiate that structural interventions, such as highly specific low-cost ones, can greatly raise the effectiveness of natural ventilation, decrease heat stress, and play a role in the overall improvement of welfare and productivity of semi-intensive livestock systems. In general, the research represents the relevance and scalability of passive design interventions with regard to the promotion of sustainable and climate-resilient livestock housing.