|Mader, T - UNIV NEBRASKA|
|Spiers, D - UNIV MISSOURI|
|Gaughan, J - UNIV QUEENSLAND - AU|
|BROWN BRANDL, TAMI|
|Hu, Q - UNIV NEBRASKA|
|Griffin, D - UNIV NEBRASKA GPVEC|
|Hungerford, L - UNIV NEBRASKA - GPVEC|
Submitted to: Livestock Environment International Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: March 12, 2001
Publication Date: N/A
Interpretive Summary: Heat waves reduce production and efficiency of cattle, and sometimes result in death losses. Analyses of heat wave weather records, together with observations of responses of cattle to heat challenges in the laboratory and field, have led to better information for management. This includes 1) awareness of animal responses to heat waves and high-risk situations, 2) recognition of feedlot factors (e.g, windbreaks, insufficient water) that can worsen the effects of heat waves on animals, 3) consideration of shades and other means to reduce the impact of heat, and 4) monitoring animals and local conditions when weather forecasts suggest a heat wave is developing. Following the recommendations in this report can benefit cattle in feedlots and reduce the risk for mortality during intense hot weather.
Technical Abstract: Improved management can benefit heat-challenged cattle, especially those in feedlots and other intensive production systems. Knowledge of dynamic responses of cattle to heat challenges and analyses of heat waves that have caused extensive losses, as discussed in this report, provide a basis for proactive management. Specific aspects include 1) awareness of how successive days of severe to extreme heat can interact with metabolic heat to cause high-risk situations, especially on the 3rd or 4th day, 2) recognition of feedlot factors (e.g., windbreaks, pen exposure to solar radiation, insufficient water) that can exacerbate the effects of hot weather on vulnerable animals, 3) consideration of shade and/or other heat- relief measures to reduce the exogenous heat load, and 4) monitoring of animals and local conditions when weather forecasts suggest an impending heat wave, especially when heat wave conditions are expected to reach the "strong", "severe", or "extreme" categories as described in this report. Preparations should be made for emergency tactical actions, such as wetting unshaded animals, if respiration rates exceed 180 breaths/min.