Abstract Maintaining the nutritional quality of stored concentrates is crucial for the health and productivity of dairy herds, particularly in tropical climates where high temperatures can accelerate feed degradation. This study aimed to monitor the effects of temperature and humidity variations on the quality of pelleted concentrate feed in steel silos under real-world Brazilian farm conditions during 28-day storage. Three 4-ton steel silos containing concentrate feed for lactating cows were evaluated on a dairy farm in southern Brazil. Internal and external temperature and humidity were recorded continuously. Samples were collected weekly (D0-D28). They underwent bromatological, physicochemical, and microbiological analyses (vitamins A and D3, fatty acids, total aerobic count, and mold/yeast counts). Despite extreme conditions (50 °C, 90% relative humidity) in the steel silos, microbial counts remained stable. However, vitamins A and D3 decreased significantly (233 ± 12 to 132 ± 13.08 µg/100 g dry matter (DM) and 1,577 ± 74 to 929 ± 295 IU/kg DM, respectively; 15–20% loss), while other nutrients remained stable. While metallic silos effectively preserve the quality of bulk feed in the short term, significant thermosensitive nutrient losses occur under tropical conditions. Farmers should align storage durations with seasonal climate patterns and consider protective technologies for vitamins. The findings highlight the need for comparative studies of storage methods and practical solutions tailored to tropical dairy systems, where nutrient preservation directly impacts milk production economics.
Bordin et al. (Wed,) studied this question.