Animal agrivoltaics facilitates the sustainable intensification of sheep production in tropical areas

Abstract

The field of animal agrivoltaics investigates the use of solar panels as a shading resource for production animals. The field integrates the production of animal protein with an abatement of heat stress, providing better sustainability in a given area. The present study investigated the impact of animal agrivoltaics on heat strain indicators and performance of feedlot sheep. Fifty-two non-castrated crossbred lambs (F₁, Santa Inês × Dorper) entered the feedlot with an initial body mass of 35 kg (SD = 0.4) and were fed for 60 days. Half of the lambs were assigned to pens that had shade provided by 20 modules of solar panels (VOLT; area of shade projected = 1.53 m² animal⁻¹), while the other half were assigned to a conventional feedlot system (CON), with no shade available. We assessed subcutaneous temperature, respiratory rate, and behavioral responses as indicators of thermal strain. Individual feed intake and sheep performance was measured using RFID electronic feeders (e.g., dry matter intake, daily weight gain (kg) and gain/feed ratio) and were compared between treatments. The heat load experienced by sheep was summarized into a single variable that integrated six meteorological variables. The lambs were exposed to 41 hot days. On those hot days, from 10:00–14:00 h, the VOLT lambs were more likely (P = 0.0001) to be in the shade projected by solar panels than in the sun, and the VOLT lambs had subcutaneous temperature that was 0.70ºC (P = 0.0001) lower, and respiratory rate that was 70 resp min⁻¹, lower than the CON lambs. The VOLT lambs spent more time lying (P = 0.0001), ruminating (P = 0.0001), and consumed less feed (P = 0.0001), than the CON lambs, which resulted in a 4 % improvement in the gain/feed ratio (P = 0.0002). During the 60 days of the trial the shading structure generated 2.3 MWh, and 13.70 MWh of electricity for the year, thereby preventing 7.2 tons of CO_2e to be emitted to the atmosphere. Our results confirm that animal agrivoltaics can enhance the sustainable intensification of sheep production in tropical areas, as it effectively relieves heat stress, improves animal performance, and has environmental benefits.