Mass generation rates of ammonia, moisture, and heat production were measured for mice that were housed in standard shoebox cages at a density of five mice per cage and maintained in either a 35% or 75% room relative humidity. Two mouse strains kept on two different types of bedding materials were compared when bedding material had been in the cages for two, six, and ten days. Gas exchanges directly measured were ammonia, water vapor, oxygen, and carbon dioxide. Water balance was calculated from gain in bedding weight, drinking water consumption, partial pressure of water vapor, and metabolism (CO₂ produced and O₂ consumed). All measurements were taken on the second, sixth, and tenth day of each test. All weight and volume measurements were obtained in the home environmental chamber in which the mice were housed. Gas exchanges were obtained after four cages of five mice each had been placed into one of three open system calorimeters. Relative humidity was not controlled in the calorimeters because it would have led to erroneous ammonia generation measurements.

Units: Dual