Over the last 25 years, researches in all aspects of ruminant nutrition were intensified. Forecasts indicate that in the year 2050 the world production and consumption of meat will be almost the double of the current volume, reaching 455 million tons per year. These projections are the result of human population growth, estimated at nine billion by the year 2050, and by the increasing of the purchasing power and quality of life will also increase the demand for animal protein. Relevant researches about feed efficiency, digestion and absorption processes, the development of new techniques for evaluating food and in-depth knowledge of ruminal microflora allow to the maximum use of nutrients for animals, also reducing the disposal of waste in the environment, another area of great concern. With a theme with such importance, the aim of this paper is to perform a brief explanation about the "State of Art of Ruminant Nutrition". Given the vast potential of research, we selected some current issues with global significance, especially with use in bovines, as the use of beta-agonists, use of essential and functional oils and the use of molecular biology techniques to study the microflora rumen.