Every fall you hear the drumbeat: It’s time preg check your cows! Get it done now! For producers in the Midwest who are trying to finish up harvest, pregging cows seems like the least of our concerns. It would be easier to just wait until they come off cornstalks in January. And let’s face it, the cornstalks are “free” feed. So, is it better to preg check before going to stalks or after?

To answer this question, we need to keep three things in mind: What are our actual feed costs, in what condition do we plan to marketing cows, and what are the seasonal price trends for cull cows? Other aspects are important, such as when to deworm and what product to use or whether to use scour vaccines, but they are of secondary economic importance to these big three components.

Cornstalk costs

So, we must ask first if our corn stalks are actually free. There is no question they are inexpensive feed and that grazing cows is a simpler, less expensive way to utilize them compared with baling. However, corn stalks are deficient in protein. This can be delivered in a number of ways at a reasonable cost. But remember they still take money out of your wallet. Hence, complete rations while cows are on cornstalks may be inexpensive, but not “free.”

This means your open cows are accruing expenses daily without having a calf to pay for them. At this point, that open cow needs to be looked at more like a feeder animal. This means we need to keep our cost of gain below our selling price or we lose money. As I write this post, cull cows are bringing $55-$61 per hundredweight at my local sale barn. Is your cost of gain less than this? Obviously, this price can and will change, but it is a starting point for our calculations.

Need body condition?

Of course, the price you receive depends on the cows you bring. This leads to our second point, in what condition do you plan on selling cows? For cows that are a too thin coming off grass, they will need more condition if you want to capture their full price potential. Considering the bred cows are likely too thin as well, both will benefit from adding flesh.

But are cornstalks a good way to add that flesh? It depends on how much of that cornstalk ration is actually corn. While the corn has the ability to add gains, the stover is basically a maintenance diet. With modern combines leaving so little corn in the field, it’s likely that it will require more than just a little protein supplement if you want to add flesh on stalks. This needs to be accounted for in the cost of gain equation.

Seasonal price trends

The only way to cover those expenses is with an increased sale price, which leads to our third point: What are the seasonal price trends for cull cows? Economist Derrell Peel with Oklahoma State University reports that cull cow prices increase seasonally from January into February, with a typical peak in May. December usually is the low point.

While prices and trends do not predict the market every year, they are a good index to utilize. This could potentially give the edge to holding cows until well after cornstalk grazing. Nonetheless, to play this game you need to sell the cull cow that will bring top dollar. Which means she needs to be in the right condition, and possibly also bred. And doing so must not exceed your cost of gain. Can you do this on cornstalks?

With all these points, the benefit to holding cows longer prior to preg checking accrues when they are managed to produce gains. The joy of cornstalks is to manage them extensively so we don’t need to work so closely with the cattle. So unless you plan on using your stalks as an adjunct to a feeding program to put weight on the cows, waiting to preg check until after the cows come off stalks likely costs you money. In times like these when the pencil is being pushed to the breaking point, it works better to identify those open cows ASAP. That way, they either can be marketed immediately to save on feed costs, or be put on a cost-effective ration to grow so they can be sold later at the correct size.

The opinions of the author are not necessarily those of Beef Producer or Farm Progress.