Respiration Rate Predictive Equation and Effective Heat Stress Relief Ways for Hanwoo Steers

Abstract

Normalizing respiration rate in heat-stress challenged cattle during summer season is very important. In this study, we investigated the contribution of different thermal factors such as skin temperature, dew-point temperature, solar radiation, dry-bulb temperature and wind speed on its influence to the respiration rate dynamics of 45 Hanwoo steers in 2010. Secondly, the heat insulation efficiencies of the three kinds of roofing materials such as sandwich panel (SP), master panel (MP), and fiber glass reinforced plastic (FRP) were computed by using our newly-developed respiration rate predictive equation for Hanwoo steers. Among the thermal factors, we found out that skin temperature, dew-point temperature and dry bulb temperature mostly influenced respiration rate. Skin temperature was stimulated by increased dry-bulb temperature and solar radiation. Our newly developed respiration rate predictive equation also indicated the positive contribution of wind speed to alleviate heat load of Hanwoo during high ambient; temperature, therefore fans should be used for inducing wind speed to 1.0 similar to 1.7 m s(-1) under summer heat stress. Conclusively, sandwich panel could be the most recommendable roofing-type to normalize respiration in heat-challenged Hanwoo steers.