An investigation of the effectiveness of sprinkling to suppress dust and of its effect on the temperature and relative humidity in open cattle feedlot pens is reported here. One sprinkled feedlot and one unsprinkled feedlot, located in the Imperial Valley of California, were studied. Typical values of temperature and dew point temperature, as a function of time of day, are presented which illustrate their variability within each lot and between lots. The results indicate that: (1) A program of sprinkling the pens for 2 hours, beginning at 1 pm PDT and again for 1½ hours beginning about 5 pm PDT, should reduce the total dustiness by at least half. (2) Sprinkling appears to reduce the maximum temperature reached for the day (< 10°F) while raising the ambient relative humidity by not more than about 10%. (3) No deleterious effects on animal performance, morbidity, or mortality resulted from sprinkling. (4) No increase in fly or odor problems could be traced to sprinkling.

Support for this study was provided by L'SD A-ARS, CRBA, the University of California Agricultural Extension Service, the Department of Agricultural Engineering, U.C. Davis, Calif., arid the California Cattle Feeders Association,. Richard Zinn assisted in. servicing the sampling stations: and Ralph Temps reduced the strip chart data. to card form. C, R. Miller and G. I. Peigt assisted in the installation, maintenance and repair of the equipment at the site.