Abstract
The purpose of this study was to examine the effect of a shade shelter in decreasing the heat stress resulting from hot summer grazing. A shade shelter was constructed in a wild grass grazing area. The roof material consisted of two sheets of 1 mm mesh black “Kanreisa”. Environmental parameters were measured every 6 days in both the shade and sunshine sections. There were significant differences in globe temperature (GT), and effective temperature (ET (DBT, GT)) between shade and sunshine sections. Physiological parameters of the cows were measured every 3 days in both the shade and sunshine sections. In 2006 the rectal temperature (RT) of cows in the sunshine section was higher than in the shade section. There were significant differences (P < 0.01) in both groups of cows. In 2007, the RT of cows was not significantly different, except for one cow between the sunshine section and the shade section. In 2006 and 2007, there were significant differences for mean body temperature (Tb) and respiration rate (RR) between the sunshine section and the shade section. As a result of using the shade shelter made by “Kanreisa” Tb and RR remained lower. On another day the utility of the shelter was observed by a video camera. While grazing the shade shelter was used more than 60% in the day time. It was useful to reduce the heat stress in grazing Japanese Black cows by shelters that were constructed of 1 mm mesh black “Kanreisa”.
