When reducing heat stress in dairy herds, fans are used to enhance the evaporation of moisture from a cow s back. Fan selection should be based on performance rather than horsepower and diameter. Certified lab studies of similar size fans show a 50 percent difference in airflow rate per unit of input energy. Maintenance is important to ensure desired performance and to prolong equipment life. The first freestall barn design criteria to consider should be the orientation of the structure.
Sunlight enters north-south oriented barns directly in the morning and afternoon.
While afternoon sun is the most detrimental, morning sun also can affect cow behavior during hot weather. Because cows seek shade in summer, direct sunlight will reduce stall usage, especially stalls located on outside walls. It is also important to consider that with greater sidewall heights, afternoon sunlight can reach much of the west half of the structure. Protection from direct sunlight is vital for effective heat stress abatement. This text was extracted from the publication, EP75.