In this studies the functional characteristics of the active glucose transport of isolated ruminal epithelia was investigated. A net movement of glucose on isolated ruminal epithelia is measurable. The presence of functional active proteins of sodium/clucose cotransporter on ruminal epithelia was confirmed. The activity of sodium/glucose cotransporter depends on diet. Feeding concentrate induces a reduction in active transport. Food deprivation reduces the transport capacity and increases the affinity of the transporter to glucose. The influence of diet on morphological structures of ruminal epithelium was investigated in addition.