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Zoneamento bioclimático e impactos das mudanças climáticas para a bovinocultura de leite no Estado do Maranhão

2026-07-30T00:00:00Z

Título: Zoneamento bioclimático e impactos das mudanças climáticas para a bovinocultura de leite no Estado do Maranhão Autor: SOUSA, Andressa Carvalho de Primeiro orientador: MACHADO, Nítalo André Farias Abstract: Bioclimatic zoning is an important tool for dairy cattle production, as it allows the identification of areas with greater vulnerability to heat stress and supports management strategies, territorial planning, and adaptation to climate change. Therefore, this study aimed to perform bioclimatic zoning and assess the impacts of climate change on dairy cattle production in Maranhão, Brazil. The spatial and temporal variability of environmental heat load and its effects on heat stress risk in cattle were evaluated using the Temperature-Humidity Index (THI), calculated from historical data (2012–2023) and future climate projections under the intermediate (RCP4.5) and pessimistic (RCP8.5) scenarios derived from the Eta/INPE model. Meteorological data on air temperature and wind speed were obtained from the TerraClimate platform. Decline in Milk Production (DMP) was also estimated for cows with production potentials of 10 and 25 kg cow−1 day−1. Spatial variability was assessed using geostatistical techniques, including experimental semivariogram fitting, ordinary kriging interpolation, and thematic mapping. The THI results revealed a decreasing thermal gradient from north to south, with the largest areas presenting THI values above 80 occurring in 2012, 2013, and 2015– 2017, indicating a higher risk of heat stress. Furthermore, DMP was more pronounced in high-producing dairy cattle due to their greater metabolic heat production and higher energy requirements associated with lactation. Climate projections indicated that, under the RCP4.5 scenario, more than 60% of Maranhão may present mean THI values between 78 and 81 by the end of the century, with losses exceeding 1.5 kg cow−1 day−1 for moderately producing animals and 4 kg cow−1 day−1 for high-producing animals in the long term. Under the RCP8.5 scenario, the expansion of areas with THI values above 86 is projected, corresponding to emergency heat stress conditions, with estimated losses exceeding 4 kg cow−1 day−1 for moderately producing animals and 9 kg cow−1 day−1 for high-producing animals. The results indicate high vulnerability of dairy cattle production in Maranhão to heat stress and reinforce the need for adaptation strategies, including the selection of animals better adapted to local climatic conditions, improvements in housing facilities, shading, ventilation, adequate water availability, adjustments in feeding management, and cooling systems. It is concluded that bioclimatic zoning can support the identification of priority areas and guide management and production planning strategies, contributing to increased resilience and sustainability of dairy cattle production under climate change. Instituição: Universidade Federal do Maranhão Tipo do documento: Dissertação

Estresse térmico em ovinos: zoneamento bioclimático com estimativa da redução do consumo alimentar no estado do maranhão e avaliação da termografia infravermelha ocular

2026-07-28T00:00:00Z

Título: Estresse térmico em ovinos: zoneamento bioclimático com estimativa da redução do consumo alimentar no estado do maranhão e avaliação da termografia infravermelha ocular Autor: SANTOS, Cyntia Airagna Fortes dos Primeiro orientador: MENEZES, Kamila Cunha de Abstract: Global warming poses increasing challenges to livestock farming, making heat stress one of the main limiting factors to productivity and animal welfare. The objective of this research was to investigate climate risk and adaptation strategies in sheep production and welfare in Maranhão using two complementary approaches. In Chapter I, a literature review on the topic is presented. In Chapter II, the bioclimatic zoning of Maranhão was carried out via monthly calculation of the Temperature and Humidity Index (THI) and the Black Globe Temperature and Humidity Index (BGHI), using meteorological data from the TerraClimate platform (2014–2024). Geostatistical modeling via ordinary kriging was used to generate thematic maps of the spatio- temporal distribution of heat stress risk (THI and BGHI) and estimate the associated reduction in feed intake (RFI). The results showed high susceptibility to annual heat stress throughout the state of Maranhão, with intensification in the second half of the year, especially between August and November. The North and East mesoregions concentrated the highest values of ITU and ITGU, while the South mesoregion presented the highest relative bioclimatic suitability. The RCA estimate exceeded 4 kg animal−1 d−1 in the Central and East mesoregions in October, evidencing severe productive impacts. In Chapter III, the efficiency of ocular infrared thermography as a non-invasive method for detecting thermal stress was evaluated. Six crossbred sheep (Santa Inês × Dorper) were subjected to three controlled temperatures (26, 29, and 34 °C) in a climatic chamber, with measurement of heart rate (HR), rectal temperature (RT), in addition to productive parameters and thermographic temperatures of the regions of interest (ROI): ocular, pupillary, and lacrimal sac. Exposure to 34 °C caused significant increases in RR and RT, as thermoregulatory responses. There were reductions in weight gain (21%) and dry matter intake (38%) and an increase in water intake (39%). The thermographic temperatures of the ROIs responded progressively to the thermal increase. Eye temperature stood out as the most accurate estimate and consistent with the RT, demonstrating that it is a non-invasive, practical method for the monitoring of heat stress in sheep. Instituição: Universidade Federal do Maranhão Tipo do documento: Dissertação

PUPILOMETRIA COMO INDICADOR NÃO INVASIVO DE ESTRESSE TÉRMICO EM OVELHAS

2026-05-29T00:00:00Z

Título: PUPILOMETRIA COMO INDICADOR NÃO INVASIVO DE ESTRESSE TÉRMICO EM OVELHAS Autor: MARINHO FILHO, Lourdivaldo dos Santos Primeiro orientador: MACHADO, Nitalo André Farias Abstract: The aim of this study was to evaluate pupillometry as a technique for detecting heat stress in sheep under controlled environmental conditions. Six crossbred Santa Inês × Dorper ewes, approximately 7 months old and with an initial body weight of 23.70 ± 5.73 kg (mean ± SD), were assigned to a completely randomized design with repeated measures and exposed to three controlled air temperature conditions (26, 29, and 34 °C; 65% relative humidity) in a climatic chamber under standardized lighting. Pupillary area (PA) was obtained from video recordings by extracting images and processing them manually for analysis. Thermoregulatory responses, including respiratory rate (RR), heart rate (HR), and cortisol, among others, were also evaluated. Means were compared using Tukey’s test, and associations were assessed using Pearson’s correlation (P ≤ 0.05). PA increased by 16.05 mm² (≈20%) between 26 and 34 °C. RR and HR increased progressively across 26, 29, and 34 °C (P < 0.001), while cortisol increased by approximately 66% (P = 0.01). Strong positive correlations were observed between PA and RR (r = 0.88), HR (r = 0.87), and cortisol (r = 0.84). In conclusion, pupillary dynamics are associated with thermoregulatory responses in ewes exposed to heat stress, highlighting the potential of pupillometry in production animals. However, further research is needed to develop technological solutions that enable practical on-farm applications. Instituição: Universidade Federal do Maranhão Tipo do documento: Dissertação

Silício e bactérias fixadoras de nitrogênio na qualidade de silagens de milho com e sem espiga

2025-10-31T00:00:00Z

Título: Silício e bactérias fixadoras de nitrogênio na qualidade de silagens de milho com e sem espiga Autor: OLIVEIRA, Jéssica Maria de Sousa Primeiro orientador: FERREIRA, Daniele de Jesus Abstract: This study aimed to evaluate the effects of inoculation with Azospirillum brasilense and the application of different silicon doses on the chemical composition, macro and micromineral composition, microbial population, fermentation profile, and aerobic stability of corn silages, with and without cobs. In the first chapter related to corn silage without cobs, the average contents of nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, and sodium showed no significant differences (P > 0.05) in any of the specific factors. The nitrogen content ranged from 1.57 to 1.62 g kg−1 between treatments with and without inoculation. For microbiology, the average counts of lactic acid bacteria (LAB) were 0.976 and 2.093 log10 CFU g−1 for silages without and with A. brasilense, respectively, with no significant effect (P = 0.171). Filamentous fungi (MOLD) counts ranged from 3,318 to 3,143 log10 CFU g−1 (P = 0.651) and yeast counts from 0.773 to 1,128 log10 CFU g−1 (P = 0.160). There was no interaction between silicon and inoculant (P > 0.05). Gas and effluent losses were reduced, and aerobic stability was maintained for over 120 hours. In the second chapter, concerning corn cob silage, a positive influence of inoculation with A. brasilense and increasing silicon doses on the fermentation profile and chemical composition was observed. Dry matter (DM) contents ranged from 45.3% to 48.7% (P = 0.041), with an increasing trend at higher silicon doses. Inoculation reduced N-NH3/TN levels, reducing protein release (P = 0.038). Fermentation losses were significantly lower (P < 0.05) in silages with inoculant and with 8 kg ha−1 of silicon, reflecting better dry matter conservation and lower effluent production. Aerobic stability showed a significant increase, exceeding 140 h for the combined treatments, while treatments without inoculant or without silicon reached only approximately 96 h before a 2 °C increase in silage temperature. The relationship between higher dry matter and lower fermentable substrate loss suggests that silicon contributed to the structural integrity of the grains and reduced undesirable microbial activity, while A. brasilense favored the rapid colonization by lactic acid bacteria and a consequent drop in pH. This synergy resulted in greater aerobic stability and maintenance of nutritional quality after silo opening. Overall, it can be concluded that the combination of silicon and A. brasilense is an efficient strategy for improving the improvement and conservation of corn silages, especially in the ear fraction, promoting increased dry matter, reduced losses, and greater aerobic stability, without compromising the nutritional value of the forage. Instituição: Universidade Federal do Maranhão Tipo do documento: Dissertação