Recording of Thermal Factors in Dairy Barns

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Abstract
A scheme for recording thermal factors in dairy barns was worked out and used in 53 herds during Oct.-Jan. Recordings were undertaken in predefined points, once in each herd, by means of indicating instruments which provided instant values for air temperature, velocity and cooling power (katavalue). In many of the barns the thermal conditions varied considerably along a row of cow stalls, and the temperature in a stall at 10 cm above floor level often differed widely from that in the center, 120 cm above the floor. In order to get a representative picture of the thermal conditions, recordings must be undertaken at different locations and heights. Recordings of air velocity by means of the hot wire anemometer were of limited value. The kata thermometer provided valuable data about combined effects of thermal factors. This instrument was less suitable for estimating air velocity, as a high discrepancy was seen between estimated and measured velocity at outdoor temperatures below 0.degree. C. Use of the kata thermometer is laborious and time-consuming. For routine field use, recording of air temperature at different locations, supplemented with observations of air movement patterns by means of tracer gas provides useful information about thermal conditions. The present recording scheme did not provide data which can be used in field studies on the influence of climatic factors on livestock diseases. The method was suitable for studying climatic effects of different housing systems and designs. It is of value as part of herd health evaluations.