[The relationship between the acidity of the rumen contents and the proliferation status of the rumen mucosa in cattle].

Two non pregnant, non lactating Jersey cows, fitted with rumen fistulas, were subjected to three feeding periods: high - low - high in energy. At the end of each period biopsies (approximately 1 cm2) were taken from the floor of the dorsal blind sack of the rumen for morphological examination. After in-vivo-isolation of the ventral sack of the rumen a mixture of volatile fatty acids (pH 5) has been infused and the time measured in which the pH value rose from 5 to 7. The ruminal mucosa reacted to the different energy levels of the ration, as expected, by proliferation or regression. With high mucosa the pH of the infused solution rose, at the maximum, 100% faster to pH 7 than with low mucosa. On that way the different absorption capacity of the ruminal mucosa as well as their importance for the regulation of the pH value in the rumen could be demonstrated.