Critical Temperature

As a result of reading a very informative post by a website called igrow explaining the deaths of the livestock, cows, horses & sheep, in the recent blizzard in South Dakota on October 4, 2013. A very well written explaination on critical temperature and the stress the unpredictable environment can cause on a cow or horse - lead me to want to share and save the information for future reference.

The website has a handy chart ( that I have converted from Fahrenheit to Celius), along with a PDF document regarding calves, that can be found at: https://igrow.org/livestock/beef/spring-storms-and-cold-stress/ PDF document (link) on Cold Stress and Newborn Calves

The following is explained:

COLD STRESS: wet conditions alone or combined with wind create temperature effects.
A wet coat reduces insulation that the hair and hide provide and increase the rate of heat loss from the body. The TYPE of coat (summer/winter) also affects the animals critical temperature.
CRITICAL TEMPERATURE is the temperature at which the animal must increase its metabolism, or burn its own energy to maintain its body temperature. The further the effective temperature is below the critical temperature, the more energy the animal must use to maintain its body temperature.

°C - Celcius CANADA

°F - Fahrenheit US 

I don't know how to read the chart exactly, but understand the top portion. Recently, we experienced a fast, drastic change - going from +20 degrees Celcius to -11 degrees Celcius. The horses were wet and shivering as the snow was heavy and sloppy. There was a cold wind accompanying it and their coats weren't quite grown in. They are lucky to have access to plenty of good quality hay, shelter and fresh water. As a precaution we put their blankets on - mainly to keep them dry. 

Another helpful resources/sits is the South Dakota State University website