Monitoramento bioclimático de bovinos leiteiros em sistema de produção na Amazônia

Abstract

The present study aimed to monitor the bioclimatic parameters of commercial dairy cattle production systems in the municipality of Parintins-AM. Data collection was carried out between August 2024 and September 2025 using an IBUTG-AK887 heat stress meter, which performs the following environmental measurements: Ambient Temperature, Wet-Bulb Temperature, Black Globe Temperature, Dew Point Temperature, and Relative Humidity. These parameters were used to calculate the Black Globe-Humidity Index (BGHI), following the formula: BGHI = BGT + (0.36 × DPt) + 41.5. In parallel, milk yield was recorded biweekly alongside the milk control procedure, using a milk-recording sheet that included information on milk weight and clinical and subclinical mastitis analyses, following appropriate hygiene protocols. The results showed that the evaluated environment exerted strong thermal pressure on the animals, with a mean BGHI of 83.53 and a standard deviation of (±10.43), a value classified as a danger zone for dairy cattle. Although Zebu genetics contributed to greater heat tolerance, thermal comfort limits were exceeded at all times. Throughout the entire study period, the animals remained continuously exposed to heat stress conditions, which affected milk production and overall welfare. These findings reinforce the need for management strategies, infrastructure improvements, and genetic selection aimed at thermal resilience, in addition to developing a regional thermal comfort index adapted to equatorial conditions.