ABSTRACT
Animal environments are characterized according to problems suspected of being associated with environmental stress on the animals and the effectiveness of control measures. A well-planned and organized approach to environmental-measurement programs is important. Environmental assessments are based on interpretations of measurements of pertinent variables. The most important consideration in regard to time is the length of the observation period. It should be a multiple of a well-established environmental cycle. Dozens of instruments for measuring environmental factors are available on the commercial market. Several principles have been used to measure air moisture, and three have been applied widely in quantifying animal environments. The temperatures of environmental surfaces likewise play a central role in determining the magnitude and direction of thermal-radiant flux. Qualitative studies of airborne microbes in animal environments have long involved opening a petri dish of culture medium, permitting viable particles to settle out of the air onto the medium's surface.
