ABSTRACT. This study aimed to analyze the principal components of the meteorological variables, physiological and behavioral response of cows subjected to different cooling times and their influence on milk quality, in the dry and rainfall periods, and to establish multiple regression models for milk quality. The data used in the study came from an experiment conducted in the Agreste Region of Pernambuco. The pre-milking cooling time was 10, 20, 30 min. and the control (without cooling). Sixteen multiparous lactating Gir cows were selected. Data were analyzed by principal component analysis and a multiple regression analysis was applied to determine milk quality. There was a strong relationship between somatic cell count (SCC) and activity of the animal in the shade for dry, and lying for rainfall, with increased SCC in cow milk. It was possible to establish two multiple regression models to determine milk quality in dry and rainfall periods. According to the principal component analysis, the cooling time to meet the thermal requirement of the animals was 20 min., regardless of the season and milking shift.

Resumen La región semiárida brasileña se caracteriza por la escasez de agua, lo que provoca la pérdida de hojas de la vegetación nativa para reducir la transpiración. Con la reducción del área foliar de Caatinga el suelo está más expuesto, convertirme en un gran aliado para la degradación ambiental. El objetivo fue vigilar y analizar la dinámica espacio-temporal de la vegetación de Caatinga mediante la teledetección orbital en región semiárida de Pernambuco, Brasil, en la estación de lluvias en la estación seca. Estudio se desarrolló mediante imágenes del satélite Landsat-8, entre los años 2013-2018, y mediante el algoritmo SEBAL se determinaron mapas temáticos de los parámetros biofísicos: albedo y temperatura superficial, índice de vegetación de diferencia normalizada (NDVI), índice de vegetación ajustado al suelo (SAVI) e índice de área foliar (LAI). Los resultados muestran que en la estación seca hay una aptitud más notable para que se produzca la degradación ambiental.

Abstract The Brazilian semiarid region is marked by water scarcity, which causes the loss of leaves from native vegetation to reduce transpiration. With the reduction of the Caatinga leaf area, the soil becomes more exposed, which makes it a great ally for environmental degradation. This study aimed to monitor and analyze the spatial-temporal dynamics of the Caatinga vegetation by orbital remote sensing in the semiarid region of Pernambuco, Brazil, in the rainy and dry season. The study was developed from Landsat-8 satellite images between the years 2013-2018. From the SEBAL algorithm, thematic maps of the biophysical parameters were determined: albedo and surface temperature, normalized difference vegetation index (NDVI), soil-adjusted vegetation index (SAVI), and leaf area index (LAI). The results show that in the dry season, there is a greater aptitude for environmental degradation to occur.

A análise conjunta do posicionamento e da atividade de bovinos a pasto, associada aos atributos do solo, torna-se importante na tomada de decisões e manejo da forragem. Neste trabalho desenvolveu-se o protótipo de um dispositivo eletrônico de sensoriamento baseado no sistema de posicionamento global (GPS) com o objetivo de monitorar o posicionamento de bovinos de leite a pasto e associar as áreas de preferência dos animais a possíveis alterações da resistência à penetração e ao acúmulo de matéria orgânica no solo sob pastoreio. O estudo foi conduzido na Fazenda Roçadinho, região Agreste de Pernambuco, Brasil, em uma área de 40 x 40 m, manejada em sistema de pastoreio contínuo. Os sensores de posicionamento GPS foram fixados por colares no pescoço dos animais e programados para registrar a localização dos animais durante o período de pastoreio. O erro médio observado foi de 0,65 m. Antes e após o pastoreio coletaram-se 36 amostras deformadas na camada superficial do solo para determinação da matéria orgânica (0,00 a 0,05 m) e da resistência à penetração (0,00 a 0,10 m). O dispositivo eletrônico desenvolvido apresentou precisão e autonomia adequada para o monitoramento de bovinos, o que permitiu determinar locais de preferências de pastoreio. Verificou-se que após o pastoreio, houve um acréscimo de 6,5% na matéria orgânica e 79,4% na resistência a penetração do solo nos locais de maior exploração do pasto.

The joint analysis about cattle positioning and activity in pasture associated to soil attributes, become important for making decisions and forage management. In this work, the prototype of an electronic sensing device based on global positioning system (GPS) was developed with the objective of monitoring dairy cattle position in pasture and associating animal preference areas to possible changes for soil penetration resistance and organic matter accumulation. Our study was performed at Roçadinho Farm, Agreste region of Pernambuco, Brazil, in 40 x 40 m area, managed under continuous stocking method. The GPS positioning sensors were fixed by collars on the animal neck and programmed to record the animal location during grazing. The mean error observed was 0.65 m. Before and after grazing, 36 deformed samples were collected in the soil surface layer for determination of organic matter (from 0.00 to 0.05 m) and penetration resistance (from 0.00 to 0.10 m). The developed electronic device had adequate accuracy and autonomy for cattle monitoring, which allowed to determine preference sites of grazing. After grazing, there was increase of 6.5% for organic matter and 79.4% for soil penetration resistance in the sites of greater pasture exploitation.

ABSTRACT. Soils under pastures suffer physical modifications, in greater or lesser intensity, via the action of animal trampling. Thus, the aim was to evaluate the spatial dependence of soil physical attributes under bovine trampling. The trial was performed at Roçadinho Farm, Agreste of Pernambuco, Brazil, in a 40 x 40 m paddock that was managed with continuous stocking by bovines and 12 AU ha-1 stocking rate. Soil samples were collected before and after grazing using a 6 x 6 m grid, totaling 36 sampling points. At each point, the bulk density, total porosity, moisture, soil penetration resistance at 0.00 - 0.10, 0.10 - 0.20, and 0.20 - 0.30 m depth were estimated, as was the hydraulic conductivity on the saturated soil surface. Descriptive statistics and geostatistics supported the data analysis. A normal distribution was verified for all variables, which were scored as either low or high variability in terms of the variation coefficient. The physical attributes (density, total porosity, moisture, soil penetration resistance and hydraulic conductivity) of the soil sampled presented a strong spatial dependence before and after grazing.