Submitted to: Agricultural Engineering International Conference
Publication Type: Proceedings
Publication Acceptance Date: 10/20/2002
Publication Date: 1/15/2003
Citation: NIENABER, J.A., HAHN, G.L., BROWN BRANDL, T.M., EIGENBERG, R.A. 2003. HEAT STRESS CLIMATIC CONDITIONS AND THE PHYSIOLOGICAL RESPONSES OF CATTLE. PROC., FIFTH INTERNATIONAL DAIRY HOUSING CONFERENCE. 255-262. Interpretive Summary: This paper presents a summary of climate conditions leading to heat waves. It discusses the importance of temperature, humidity, airflow, solar radiation, and animal factors. The effects of heat stress on cattle can range from a loss in production to death. Animals respond to heat stress by changing their behavior and how they eat. The rate of breathing is a change that can be easily watched and is an excellent indicator of stress. While fatal heat waves are not frequent nor widespread, producers can guard against disasters. Plenty of fresh water is essential. Cattle should not be worked when there is a danger of heat stress. Water applied to wet the hide is cooling when that water evaporates. Shade reduces the solar heat load. A combination of management practices can make the difference in survival of cattle with advanced planning, recognition of the stress signs, and quick response.
Technical Abstract: Cattle are adaptable to a wide range of climatic conditions, but can be severely challenged by sudden heat waves. Repeated hot, humid environments, with little air flow or cloud cover, are periods of concern, especially if conditions persist over a three-day period without significant nighttime relief. Early signs of animal discomfort include shade seeking, reluctance to leave the waterer, and increased respiration rate. Heat distress is generally marked by open mouth panting, little or no feed consumption, and excessive drooling. Most management practices to combat the effects require planning so that shade can be provided or water can be applied to wet animal hides, thus allowing evaporation to occur. Animal handling and routine treatment should be avoided if heat wave conditions are predicted.