Feed values and the right shelter blunt the cost of winter feeding
Cold stress costs money. How much it costs depends on how you prepare for cold weather. The best management approach is to balance sound nutrition with mitigating the cold with good resting environments.
Cold stress in beef cattle results when the effective temperature an animal endures is low enough to cause the animal’s metabolic rate to increase. This compensation requires more energy to keep a cow’s critical functions going.
A cow’s “thermoneutral” zone is the temperature where the animal does not use additional energy to cool or warm herself while maintaining basic metabolism: eating, sleeping, etc. Broad research indicates a temperature of 18°F is the lowest temperature a cow with a heavy, dry winter coat will tolerate before she becomes cold stressed.
The principal factors responsible for cold stress are fairly obvious, but they do work in combination to affect total amount of cold stress. They are: lot conditions, physical activities and weather conditions.
In the barn lot, poor conditions such as wet, muddy, unprotected resting and feeding areas mean extra work for your cows to stay warm. It takes extra energy to maintain body temperature with a wet or matted hair coat. Polar bears might burrow into deep snow to stay warm, but the same trick does not work well for cows. To compensate for this fact, cows will increase their feed intake to meet the increased energy need.
Years ago, when unrolling hay for cows on the Dakota/Minnesota border, I would sometimes see cows lay on the hay before they ate. There seems to be a point where, for a cow, it is more important to rest than to eat. The absence of dry resting and feeding areas can be a significant factor in cold stress. Providing adequate bedding reduces the animals energy requirement. It saves feed and keeps weight on cows.
In addition to lot factors, cow body condition can erode when the animals are not meeting their required nutritional needs. Sometimes this occurs because a producer might have used the nutrition algorithm of “the feed that is cheapest wins.” The result of that plan is that you might be unable to meet the herds’ nutrient needs because feeds were bought according to cost rather than nutrient value. Feeds that can’t meet nutrition requirements in cold weather can be the beginning of a fix that ends up costing more than better feed would have to begin with. If it is cold, wet and windy, I can end up with cows really deep into the Cattle Charge bin—and really quick.
If adequate feed energy is not provided during extremely cold conditions, the cow will use body fat to meet her requisite energy needs; additionally, it is likely that she will also mobilize body protein out of muscle tissue, losing both body fat and muscle. If this happens for an extended period of time, cows use up excessive body fat and muscle. After that, they might end up in the mortality column.
Wind chill and lower temperatures are major players in determining a cow’s energy needs. Wind chill effects can be reduced by providing windbreaks. Having at least a 50 percent solid break is requisite, and having it covered to help keep them dry will further reduce the amount of feed required to keep their body temperature where it needs to be.
As an example, let’s assume a mid-gestation beef cow that weighs 1,350 to 1,400 pounds. She is going to need about 24 pounds of dry matter and 12 pounds of TDN per day if it is a comfortable 30 degrees F and dry. However for every two degrees F the temperature drops, she will need another half pound of TDN, or, for rough figuring, a pound of hay.
As the temperature drops, there soon comes a point that she will not be able to eat enough hay. At that point, the higher energy needs will only be met by feeding additional concentrates. And that too will hit a limit.
To budget for winter feeding (both economically and in terms of feedstuffs), it is important to know the nutrient value of forages and feeds on the farm. By using feed analyses you can more closely match the nutrient needs of the cow and reduce winter feeding costs. You certainly do not want to underfeed cows. Overfeeding is wasteful. Knowing the nutrient content and feedstuff inventory gets you closer to matching their nutrient needs without overfeeding or underfeeding them.
Feed sample analysis is a nominal cost in the expense column for a livestock operation. And, knowing the nutritional value of the feed and forage on your farm can potentially save substantial expense. It will cost you to overfeed. And it’ll cost you if you underfeed. But if you know what you’re putting in the feeders and keep your cows in condition, they’ll calve easier and breed back better. You’ll get a better paycheck for your effort.
Dr. White is ruminant nutritionist for MFA Incorporated.