Evaluation of dairy heifers’ drinking behavior dynamics in agrivoltaic systems in a tropical region

This study aimed to evaluate the effect of an agrivoltaic system on the water intake behavior of dairy heifers raised in a tropical climate. The experiment was conducted between July and August 2025, during 12 consecutive days at FMVZ/Unesp–Botucatu, São Paulo State, Brazil. Visits to the water trough of 21 dairy heifers (550 ± 55 days old; 247 ± 37 kg, mean ± SD) were registered continuously from 9 h to 16 h. In a crossover design, the heifers were divided into three groups (7 heifers/group) and located in three pasture systems: an open pasture system (OPS), an agrivoltaic system with horizontally arranged photovoltaic panels (AGRIhor), and an agrivoltaic system with vertically positioned panels (AGRIver). The agrivoltaic systems comprised 72 panels divided into 6 paddocks (12 panels/paddock). The data were analyzed using a generalized linear mixed model (Poisson family), considering treatment and hours as fixed effects and date as a random effect. In total, 334 water intake events were recorded in the OPS, 343 in the AGRIhor, and 305 in the AGRIver. There was no effect (p>0.05) of agrivoltaic systems in relation to OPS. However, a difference was found between agrivoltaic systems (p = 0.02). The AGRIhor had, on average, 23% more events of water intake than AGRIver. Additionally, there was an interaction (p<0.05) between treatment and hours. The number of water intake events decreased progressively over the observation hours, with a decrease of 22% to 42% compared to the beginning of the observation. The highest number of water intake events (196) was recorded in the first hour of observation (9 h–9:59 h), while the lowest number of events (94) occurred between 12 h and 12:59 h. In conclusion, the arrangement of the agrivoltaic system influenced the heifers’ water intake behavior, indicating that the shading generated by agrivoltaic systems, especially in the horizontal configuration, can modify the behavioral dynamics of heifers in tropical conditions.