EVALUATION OF EVAPORATIVE COOLING ON THE CHANGES OF CATTLE SURFACE BODY TEMPERATURES WITH USE OF THERMOVISION

Air temperatures above 25 degrees C negatively influence the organism of cattle and cause heat stress. The result of this is a decline in mi lk production, feed consumption, problems with reproduction, etc. But water evaporative cooling improves cattle comfort and lessens the effe cts of high environmental temperatures on animals. Our aim was an expe rimental investigation of evaporative cooling effect on the changes of surface body temperature by means of thermovision and to determine th e hottest regions on cattle body during high air temperatures. The eff ect of evaporative cooling was investigated in 10-month-old heifers. H eifers were kept in a special climatic barn with air temperatures from 27 to 31 degrees C. The application of water was practised from speci al spray nozzles (1 m above body of animal). Time of spraying was 1 mi n. Thermograms of bodies were obtained with a special thermovision set . The thermal profiles were recorded immediately before and after spra ying, then 15, 30 and 45 min after spraying and after drying up of ani mal (an example: thermogram I-VI). After evaluation of all screen pict ures the hottest regions were found out: neck region, shoulder and rib region; the second hottest regions were underrib region, hunger pit a nd body hindparts, the third hottest regions included throat region, w ithers and sacral region (Fig. 1). Heat loss is the most intensive in these regions. After water cooling surface body temperature decreased approximately about 1.2 degrees C in all three regions. The changes du ring evaporative process are demonstrated in the pictures (Figs. 2-6). Time of spraying (1 min during temperatures 27-31 degrees C) is suffi cient for cooling down animals for 45-60 min.