The objective was to evaluate the effect of energetic supplementation on feed intake and ruminal fermentation of proteins in two protein levels in the diet (6 and 20%). There were used four rumen fistulated crossbred steers in a Latim square and the treatments were arranjed in a 2 × 2 factorial, in which the combinations were: A. only hay; B. hay + 2.8 kg of soybean meal; C. hay + 2.8 kg of corn meal; and D. hay + 2.8 kg of soybean meal + 2.8 kg of corn meal. Four experimental periods of 18 days were used, in which seven was for adaptation, seven for determination of dry matter intake and four for sampling. Ruminal samples were collected at 0, 2, 4 and 6 hours after feeding for determination of ammonia, pH and VFA. There was no interaction between corn meal and soybean meal, as well as no sampling time effect on the evaluated parameters. Soybean meal decreased 13% acetate:propionate (A:P) ratio and increased 41.2% DMI, with no effect on forage intake and pH and increased ammonia (790%), propionate (48%), total VFA (39%), isobutyrate (165%), isovalerate (208%) and valerate (201%). Corn meal did not affect protein fermentation, although it caused increase in DMI (35%) and decrease in ruminal pH (6%) and A:P ratio (18%).
ammonia; deamination; intake; pH; protein; supplementation
