It is time to put seed corn in the ground for the 2025 crop in many parts of the U.S. This is the beginning of quite a complicated process. No matter the effort or dedication, this planting, growing, and harvesting is at risk for numerous negative influences or events between now and when the final tire is thrown on the top of the bunker in the fall.

Though my efforts are adjacent to the agronomic process that brings a silage crop to completion, I do care deeply about the level of success, as I will be expected to work with what we have when the pit is opened. Some parts of the country have greater potential risks than others. In some geographies, limited water and dry periods are the greatest risk. In other areas, it may be hail, insect pressure, or plant disease. Another risk may be tight input budgets and the temptation to reduce cost for improved crop management strategies.

I like using milk per ton as a broad description of the nutrient supply of the silage. I am trying to not lean on the term “forage quality” as much as in the past. I am thinking more about the nutrient content of the forage and how the blend of milk’s building blocks will meet the particular needs of a ration. I am not sure anyone can identify exactly what the characteristics are of high-quality silage, as it truly depends on the needs of the ration it will be fed in.

We can agree, though, on what qualifies as poor-quality forage. You know it when you see it. These obvious characteristics relate to things like mold, mycotoxins, high ash, content butyric acid, excessively high or low dry matter contents, and poor packing density.

So instead of quality, let’s look at nutrient content. Yes, it is true, in the vast majority of cases the lower fiber, higher starch corn silage and the lower fiber, higher protein small grain or alfalfa is probably the most desirable option. A concept to take this one step further is to remember that the nutrient supply or even milk support per ton, resulting from a good and recently updated formula, doesn’t necessarily cause the cows to actually produce more milk. In extreme cases, where supplemental ingredients are not available or economical, the nutrient content of the primary forage in the diet might be the major determinant of actual milk production. In most cases, the real mover will be the final feed cost of the ration.

Getting it right

The concept of ration modelling gives us the opportunity, and the responsibility to feed rations that are balanced for maximum milk production no matter the nutrient content of the primary forages. In most cases of normal agronomic variation and other noncrop failure risks for forages, the true impact on variations in things like milk per ton or relative feed quality will be the feed cost to support high milk production in the ration. Except in rare circumstances, lactation rations are built to support maximum milk production. If a corn silage, for instance, has lower milk per ton, the issue is that high cow ration is going to cost more.

Let’s look at an example. I found two recent corn silage analyses from a client’s dairy that had differences in nutrient content due to some growing condition variances. The better quality silage showed a little less fiber that was more digestible and around 39% starch. The milk per ton calculation resulted in a value of around 3,000. The lower quality silage had more fiber that was less digestible and measured 33% starch. The resulting milk per ton was around 2,500. There were other minor nutrient differences like silage acids, acid detergent fiber bound nitrogen (NDICP) that all favored the higher milk per ton silage.

I completed two different ration scenarios to see how these two silages might impact the cows. In the first scenario, I assumed that for some reason, we could not obtain more corn grain, soybean hulls, or perhaps fat. Instead, we subbed the corn silage in pound for pound and the ration simply supported less milk. Or in a more likely scenario, the corn silage changed without notice and no adjustments were made in the ration. Well, how much less milk and what are the economics? The ration milk support was 4.7 pounds less per cow. If we use $18 per hundredweight (cwt.) net milk price, this is a lost income of a whopping 85 cents with no difference in feed cost. This is assuming that intakes did not drop, further exacerbating the negative milk support impacts.

The more likely reality would be that a ration formulation adjustment would be implemented to help the lesser silage support the same milk. In this case, the economic question is how much will the feed cost go up when moving to the lower milk per ton silage. Before even doing the comparison, I could have assured you it would be way better than a negative 84 cents per cow. The resulting cost increase using the optimizer and current cost for things like soybean meal, canola, flaked corn, and added fat was only 17 cents per cow. I will say that presenting my client with a 17-cent feed cost boost would certainly require some explanation. However, in comparison to allowing the cows to drop almost 5 pounds of milk, the decision will be an easy one.

In reality, would the cows really drop the 4.7 pounds of predicted milk if no reformulation was accomplished? Maybe or maybe not. However, the energetics math in the model is sound and the cows would lose that milk, reduce body condition, and perhaps loose reproductive efficiency.

Making cents of the ration

So, what is the real cost of lower milk per ton silages? It is probably a combination of the two. It is for sure more difficult to formulate for high levels of milk with higher fiber silages. It will add to feed cost and might require different ingredients like higher levels of added fat. Also, in severe cases, lower feed rates of silage might be indicated resulting in higher feed rates of higher digestible fiber ingredients like soybean hulls or beet pulp.

The key is sticking to a consistent forage analysis plan and then utilizing a strong nutrition model to adjust diets to keep the milk support high and consistent. In these situations, feed cost will modulate since, in most cases, on-farm produced silages have a lower cost point. This situation may be reversed in lower rainfall areas where forage production is more difficult and higher fiber byproducts are more readily available.

In nearly all cases, formulating for maximum milk flow is also planning for maximum return per cow. We should try to grow forages with as much digestible nutrient supply as possible to support high levels of milk. Fine tuning the various shortages in nutrients from the base forages can keep the cows healthy and support high levels of milk flow, strong reproductive success, and good cow health.