By Erika Lyon
Several years ago, I wrote about some of the issues associated with extreme winter conditions — extreme temperatures, extreme precipitation and extreme wind — and what producers can do to protect their herds.
Some of the questions I ended the article with were “what happens when we have winter seasons where temperatures occasionally reach above 70 F followed by late spring frosts? How does this affect our animals in the pasture?”
With the subzero temperatures and snowfall we received this holiday season followed by warmer, wetter conditions soon after, it might be a good time to revisit this subject.
Many of our livestock can tolerate temperatures down to 20-32 F and up to 78 F. Outside of this range, animals become stressed and lose productivity.
But there is more to this than temperature alone – status of an animal (i.e. calves versus lactating cows), precipitation and windchill can increase the lower critical temperature. Temperatures must also be consistent – not bouncing from one extreme to another.
An animal that has experienced mostly sunny, 70 F weather for several months cannot go to 20 F immediately, even if 20 F is in their temperature range. They need to be acclimatized to these conditions gradually.
As temperatures gradually cool in the fall, livestock will develop thicker haircoats and fat. Fall is also a great time for producers to build up body condition that can help animals tolerate sudden drops in temperature.
When conditions go below freezing and livestock have not had time to acclimatize or have low body condition scores, they have substantially greater energy requirements to maintain body temperature and function.
Then there is the issue of mud. When temperatures go from warm to cold in a short period of time, mud in pastures can freeze, making the ground uneven and increasing risk of livestock injury.
Short-lived freeze-thaw cycles can make it challenging to get into the fields as well. What happens when the reverse happens, where temperatures go from extremely cold to warm?
Livestock that have acclimatized to winter conditions still have a thick haircoat and fat deposits that help to insulate them from the cold, which they don’t necessarily have during the warm summer months. This is when heat stress can take effect, which can lead to a reduction in dry matter intake, weight gain and milk production.
What to do
What can you do to mitigate the effects of rapid temperature change? One method is creating areas within the pasture that are protected from the elements.
For example, to reduce the effects of windchill, create a windbreak. Windbreaks can be trees, stacked hay bales or other materials that are tall but allow for some wind through gaps.
Feed high-quality feedstuffs, including forages. One of the many downsides to rapid temperature fluctuations is that conditions for mold to develop may occur, which leads to a reduction in the quality of feed. Make sure to test your hay’s nutritional quality before feeding.
If you are changing out any feeds, though, make these changes gradually. This will help animals improve their body condition.
Any pregnant animals should be fed separately from the rest of the herd so they have access to feed to meet their energy requirements. When temperatures drop and water freezes, maintain water temperatures at 37 F.
Don’t rely on the snow. Livestock such as cattle cannot lick or eat enough snow to meet their water needs. This can also decrease body temperatures on an already cold day, which leads to an increase in energy requirements. Furthermore, frozen water can limit feed intake, making it increasingly difficult to meet their energy needs.
To avoid mud, keep animals moving. Pasture rotation is a great way to do this. Rotate livestock to the next paddock before the current one turns to mud and becomes inaccessible. This can also help reduce risk of parasites — many can be active in the winter, especially after warm spells.
Large temperature swings during the cold months can help contribute to a variety of respiratory issues. Keep livestock up to date on their vaccines and consider if a pre-conditioning program is right for your operation.
Pre-conditioning focuses on health and nutrition of livestock and refers to a period of at least 45 days where a producer works to improve the immune system and health status of a weaned calf prior to sale. This includes time to acclimate calves to dry feed.
For animals housed indoors, have enough bedding with good ventilation. We came fairly close to the 70s in many parts of Ohio on Dec. 30, 2022, and a few days in January saw temps in the 60s. This immediately followed a time when we saw a period of extreme cold — in Cadiz, the temperature dropped to -5 F with a windchill in the -20s.
While these temperatures are tolerable (well, the warmer temps anyway), the rapid change in temperature makes it much more difficult to acclimatize to and will require additional management to maintain productivity.
The following resources are available for more information:
– “Heat stress: physiology of acclimation and adaptation,” by RJ Collier. Available at academic.oup.com/af/article/9/1/12/5146549
– “What is included in a preconditioning program?” by S. Stuttgen, W. Halfman and R. Sterry. Available at livestock.extension.wisc.edu/articles/what-is-included-in-a-preconditioning-program/Source : osu.edu