The effects of diets with increasing ground corn grain levels (0, 22, 37 and 49% in the dry matter) substituting coast-cross hay, with different protein:non-fibrous carbohydrate ratios (CP:NFC = 1.01; 0.39; 0.33 and 0.27) were assessed on buffalo ruminal metabolism. Four rumen fistulated buffaloes were used kept in a 4 × 4 latin square design, to collect liquid ruminal samples, collected in each experimental period (28 days) at 0, 2, 4 and 8 hours after feeding. In general, the buffalo presented good buffering capacity in the rumen, with high mean pH (6.70) and increase in ground corn intake. The increase in the corn levels in the diet resulted in increased butyric acid production. Only the diet with 49% corn showed better ruminal fermentation, with a small proportion of acetic:propionic acids. The CP:NFC ratio of 1.01 indicated energy deficiency in the diet available for microorganisms in the rumen throughout the day, although the diets with CP:NFC between 0.39 and 0.27 resulted in similar ruminal fermentations, that indicated synchronization in nitrogen and energy use by the rumen microorganisms under these conditions.
ammonia; buffalo; carbohydrate; rumen; rumen pH; volatile fatty acids
