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Evaluation of the influence of shadowing in the development and performance of milk bovines in the grass


In tropical regions, due to solar light incidence, there is a higher potential of line production and also bigger problems to milk production. The most productive animals have the highest metabolic heat production due to more production of milk, being more vulnerable to thermal heat and its consequences on productivity and sanity. This work objective is to evaluate direct and indirect influence of shadowing on animals in the grass, how it affects physiology, development of heifers and the production and quality of milk, determinate the ideal shadow area to animals and the best cost-benefit relation between different cover materials used to determinate the strip limit of thermal stress by heat. The research has four stages: the first one is a quantity-quality survey (QQS), with milk producers that use grass as main source of voluminous. The second will be a mathematic mold to determinate the projected shadow area in response to the geographic location of the necessary shelter and cover for the animals (projected area). The third one will be conducted in Piracicabna, with young animals between 18 and 20 months where the different cover materials will be evaluated. The fourth will be developed with adult animals in production fase with or without shadowing, where the shadowing effect over the quantity and quality of milk production will be analysed. As answer variability it is intended to measure environmental physics variability (dry and humid bulb, global temperature, air humidity, wind speed, radiation and precipitation) the physiological variability (rectal temperature, air temperature, respiratory frequency) and production’s variability (MS consume and digestability, weight gain, milk production and quality). Based on this parameters evaluation it is expected to provide information to production sector, willing to assist the decision made. (AU)