The objective of this trial was to evaluate the in vitro ammonia (N-NH3) production in fermentation of diets with different protein sources (dry yeast, urea and cottonseed meal) used for ruminants diets. The data relative to the N-NH3 production measured in the first hour of incubation, showed differences between diets with cottonseed meal and dry yeast, compared with diets with urea, with values of 7.52; 8.66; and 29.84 mg N-NH3/100 mL of ruminal fluid, respectively. The same pattern was observed until 12 hours of fermentation, with values of 1.05; 1.57; and 8.57 mg N-NH3/100 mL. The analysis of data related to the 12 hourly sample of fermentation showed the trend of decreasing N-NH3/100 mL concentration of ruminal fluid, reaching the lower values on 12 hours of fermentation.
ammonia; cottonseed meal; dry yeast; protein sources; ruminal fermentation; urea
