Temperature fluctuations have been aplenty around the region this year. In a span of one January day in Spearfish, South Dakota, the thermometer went from 50 degrees above zero to one below. Spearfish is more the norm than the exception. A five-day span in January brought about a 60-degree swing in Williston. In Casper, the temperature dipped to -20 and climbed to 44 within just four days. And, in Havre, MT, a seven-day run brought about a 62-degree change.
These extremes can make it hard to choose which jacket to grab for in the morning, but a cow can’t change her coat so easily. It’s no secret that as the temperatures drop, a cow’s energy needs increase. In a Northern Ag Network interview, Dr. Steve Paisley explained that for every degree below 20 degrees with wind chill, a cow’s energy requirements go up by one percent. But how do you factor in these extreme fluctuations?
Paisley looks at these quick jumps up and down as stressors to livestock. “I think there certainly is stress,” said Paisley, “on that animal from a respiratory standpoint.” He explained that cattle have proportionately small lungs as compared to their body size. When you get a big swing in temperatures, he says that impacts both the immune system and respiratory health of the animal.
On top of that, if the top end of the temperature range brings about rain and mud, you have to take into consideration other stresses. Cows may have to move through heavy mud. They may also have water on their coats keeping them cooler than they would be without it. “Those are other things,” said Paisley, “that really impact the energy requirement of that animal.”
© Haylie Shipp 2015
