The effect of protein nutrition on the urinary concentration of urea and subsequent emission of ammonia into the atmosphere was studied using a mechanically ventilated cubicle house containing 34 lactating dairy cows (cross bred Holstein Friesian and Dutch Friesian). Two silage-based diets with different amounts of rumen-degradable protein balance (OEB), were alternately fed during six 3-week periods. Diet L contained a small amount of OEB and resulted in a 39% lower emission rate, compared with diet H which contained a high amount of OEB. The concentration of urea in the urine samples was 42% lower when feeding diet L compared with diet H. A decrease in urea concentration as a result of a lower OEB could contribute substantially towards diminishing the emission of ammonia from cubicle houses for dairy cattle.
Smits, M. C. J., Valk, H., Elzing, A., & Keen, A. (1995). Effect of protein nutrition on ammonia emission from a cubicle house for dairy cattle. Livestock Production Science, 44(2), 147-156. https://doi.org/10.1016/0301-6226(95)00068-6