Ammonia emission in a scale model of a dairy-cow house

A scale model of a dairy-cow house was developed for studying factors involved with ammonia emission. The ammonia emission from two different floor fouling methods was measured. In the first case, a urine/feces mixture was applied daily to the floor surface. In the second case, a thin layer of feces was applied daily and urine was sprinkled over it. In both cases, the ammonia emission increased after fouling each day. After seven days the situation stabilized. An ammonia emission peak was always observed within two hours after application of the urine/feces mixture or the urine, while afterwards the ammonia emission rate gradually declined in about 24 h to the level prevailing before the fouling. The second method, which is more comparable to the fouling in a practical cow house, revealed a linear relationship between the height of the ammonia emission peak and the urea concentration of the urine. Measurements at different temperatures and with different air velocities over the floor surface showed that the height of the ammonia emission peak depends on temperature to the power of 0.89 and on the velocity to the power of 0.26.