The perfecting in the last years of augmentation lenses and that of the microscopes, as well as the development of samples preparation techniques, provided excellent tools in the several science areas. The evaluations at the microscope, electron or optical, of edible products utilized for ruminants, has helped in the cause/effect relationship understanding in animal performance. Of paramount importance are the advances obtained in the action mode of rumen microorganisms in the substrates knowledge, mainly of the particle-associated bacteria. Advances were also achieved in the knowledge of factors that affect the forage dry matter degradability, especially of the C3 species, but these advances also contribute to the knowledge of the C4. These studies results allowed the establishment of several research lines, creating the possibility of discrimination in the early stages of grasses and legumes selection, those which present the greatest qualitative potential. There is especial merit also in the studies to increase the corn and alfalfa stalk degradability, as well as those to identify how the agricultural byproducts treatment can increase its quality, and to verify the effect of inoculants, such as exogenous enzymes, in the dry matter degradability rate. Besides the verification of the tannin effect, especially in legumes, into the digestibility, which may in the future to foster the utilization of additives that can minimize or prevent their harmful effects on forage consumption. With relation to cereal grains, it may be verified the genotype influence on degradability. The results achieved up to now, give the base for the genetic manipulation of feed stuff utilized by ruminants, which probably will be object of research in the next decades.
alfalfa; corn; grasses; tannins
