Winter feeding programs for most beef cows include grazing cornstalks or winter range. Other receive mostly prairie hay or graze meadows. Most of these forages tend to become short on protein eventually during winter.

The protein supplement chosen is important, both in its effectiveness and its cost. Some protein sources contain urea, biuret, or other forms of non-protein nitrogen (NPN). These supplements are not effectively used by cattle when they are eating winter forages that are low in energy. All-natural protein sources are well utilized by cows grazing or being fed medium-to-low quality feeds. Soybean meal, cottonseed meal, and grain by-products all are natural proteins and are usually the main ingredients to most range cubes. However, the cheapest natural source of protein this winter is alfalfa.

When comparing protein sources, calculate their cost on a "cost per pound of protein" basis. A 40 percent protein supplement contains 800 pounds of protein per ton. If it costs $240 per ton, then the protein costs 30 cents per pound of protein. Most alfalfa hay contains at least 270 pounds of protein per ton; some approach 350 pounds. This year, prices for alfalfa vary, but most can get laid in for $60 per ton. That makes the cost per pound of protein for alfalfa 22 and 17 cents.

So when you need protein for your cows this winter, compare price on a per pound of protein basis. If you are considering a commercial protein source, keep the NPN content low.