Interannual variation of potential heat-stress of sheep in Greece during summer

Abstract

It is well known that heat-stress affects significantly physiology, welfare, health, and productivity of ruminants. This paper studied the heat-stress conditions to which sheep were exposed during the summers of a 50-year period in Greece. The Temperature Humidity Index (THI) was applied to assess potential sheep's heat-stress. Temperature and relative humidity data recorded every three hours during the summer months at four meteorological stations distributed in the country were used to calculate THI values. The interannual variation of the maximum daily maximum THI value observed every summer and every summer month separately was examined. Additionally, the daily maximum THI values, as well as the THI values recorded every three hours, which were observed every summer and every summer month separately, were classified in order to examine the interannual variation of the frequency of occurrence of the heat-stress categories defined by THI values. Descriptive statistics are presented and corresponding trends are identified. This study provides spatial quantitative results which could be taken into account when proposing strategies to improve sheep's housing conditions and when developing adaptation and mitigation strategies in the frame of climate change, at different areas in Eastern Mediterranean.