BECAUSE THEY’RE WORTH IT: Investing in a windbreak could reduce feed costs
December 17, 2014
We all know that beef cows are affected by cold, windy weather just like we are. As a result, a cow needs additional energy in her diet to maintain body temperature during periods of cold stress. If we don't supply that energy, then she will use feed energy that was intended for productive purposes (e.g. fetal growth in a pregnant cow), or will lose body condition because she will take fat off her back to get the energy.
Research done years ago at Kansas State University demonstrated that a cow's energy requirement increases by 1 percent for each degree of wind chill below her lower critical temperature, or the degrees that she goes into cold stress. The lower critical temperature for a beef cow with a dry, winter hair coat is 32 degrees F. For an example, if a cow is on a ranch somewhere near Faith, South Dakota, in January, the historical average monthly temperature and wind speed are 19 degrees and 13 mph, respectively. This creates an average monthly wind chill of 5 degrees. Thus, the cow is experiencing a 27-degree difference (32-5) between her lower critical temperature and the wind chill, which equates to a 27 percent increase in her energy requirement.
Lets take our example a little further. If we consider a good quality mixed alfalfa-grass hay at current market value, it probably costs about $1.72 a day to feed a pregnant beef cow this winter, assuming no cold stress. One economical way to supplement energy to this cow would be to feed enough DDGS (dried distillers grains) to add 27 percent to the energy value of her diet. In my ration-balancing program, this increases the cost of feed per day to $2.09.
So my question is: if you had a windbreak so that the wind speed became a non-issue, how much would you reduce the cost of feeding this cow? If we reduce wind speed felt by the cow to 0 mph, then wind chill and temperature are the same. With an average temperature of 19 degrees in January, her degrees of coldness drops to 13 (32-19), so the percentage increase in energy requirement is now only 13 percent. The ration-balancing program indicates that the cost to meet this requirement will be $1.90 per day. That is a savings of 19 cents per cow per day. Over 90 days of winter-feeding, this calculates to about $17 saved per cow.
Now that we know the feed cost savings, we can use the money saved to buy a windbreak. If we assume a 10-year lifespan for the windbreak, the feed cost saving for each cow in our herd will contribute $170 toward the windbreak. Multiply this times the number of cows in the herd that needs to be protected, and that is the budget for windbreak construction.
One might ask, why am I bringing this point up with winter upon us, and possibly frozen ground, so it is too late to dig postholes and construct a windbreak? It may be too late to construct a permanent windbreak, but temporary or portable windbreaks can still be erected. Large hay bales can be stacked to provide wind protection, plastic netting is available that can be attached to portable corral panels, and portable metal windbreak panels can be purchased that do not require permanent posts. In other words, options are available. It might be best to test designs with portable and temporary windbreaks before investing in a permanent installation, anyway.
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Reduced winter feed costs is only one reason to provide shelter from wind for cattle. General comfort and welfare is another. Additionally, the above example is based on average winter climate, but blizzards can bring temporary but much more severe wind chills, wherein windbreaks may be necessary for cow survival. In many ways, adequate protection from winter wind is a vital investment for a beef cattle operation. The point of this discussion is simply to show how the investment can pay for itself.