Heat and cold stress level categories:
|Comfort level||Map indicator||Index Value, ⁰F||General Interpretation|
|Heat Danger||> 105||Animal deaths may exceed 5%|
|Heat Caution||85 to 105||Decreased production, 20% or more
Reduced conception , as low as 0%
|Comfortable||15 to 85|
|Cold Caution||-20 to 15||18 to 36% increase in dry matter intake|
|Cold Danger||< -20|
Mader and co-workers at the University of Nebraska developed the Comprehensive Comfort Index to incorporate both extremes of hot and cold into one index value. It is unique in that it includes, in addition to air temperature and relative humidity, effects of wind speed and solar radiation. Development and validation of the index used data from beef and dairy cattle.
Actual animal response to temperature stress will be dependent on a number of factors not accounted for in the index. Those include, but aren’t limited to, age, hair coat (winter vs summer; wet vs dry), health, body condition, micro-environment and acclimatization.