Corn Silage Value
By: Ki Fanning, PHD, PAS
For the past 15 years, the price of byproducts and crop residue reduced the price that many of us could pay for corn silage (per ton) to much less than 10 times the bushel price of corn. The result is that, economically, many of us were not able to justify cutting or buying corn silage. Over the past year, the price of corn has dropped more dramatically than the price of the byproducts and crop residue. Additionally, demand for byproducts has been high due to the export markets being strong, the widespread use and the higher inclusion rates of byproducts. As for crop residue, short hay crops coupled with long winters have run forage availability short. The proliferation of bedded barns has also increased the demand for crop residues used for bedding, particularly in areas in the northern U.S.
Table 1 shows recent research results from the University of Nebraska. This study examined feeding differing levels of modified wet distillers grains (mWDG) at either 20 or 40% of the diet on a dry matter basis (DMB), with 15 or 40% DMB of corn silage. The control diet used corn stalks as the roughage source instead of corn silage. There was not a significant difference in performance between the 15% corn silage and the corn stalk diets.
Table 2 shows data from forty years ago where ADG and F:G improved with each incremental reduction in corn silage from 80% down to 10%. When applying $3.50 corn and a value of 7.5 times the price of corn for corn silage, the most profitable level of corn silage was the high level of 80%. There is no doubt that the hybrids have changed significantly as well as our farming and silage harvesting practices. Additionally, distiller’s grains have changed feeding practices. Either way, the difference in performance in the lower two levels is slight and I would argue that corn silage cannot be harvested and delivered to the bunk for 7.5 times corn’s bushel price. The old rule of thumb of 10 times the price of corn still calculates very close to most operations true value. For your own operation simply multiply the estimated bushels of corn per acre by the price per bushel (or use the total expenses per acre including land rent and taxes) and then divide by the tons harvested and then divide it by 1 minus the shrink (i.e. if shrink is 15% then divide by 0.85 or 85%). That dollar figure is your cost per ton of silage. Adjusting the corn silage price in Table 2 to 10 times the price of corn for 240 days (assuming the same days on both 10 and 80%) would reduce the magnitude of the difference in profitability from its $14 to only $5 for the 80% diet compared with the 10% diet; however, the 80% ration would still be the most profitable.
Table 3 shows the results of a study with four different levels of corn silage with 40% mWDG. Table 3 agrees with Table 2 in that ADG and F:G improve as the level of corn silage is reduced in the diet. It is also similar in the fact that the performance loss is slight when the corn silage is less than 30% of the diet (DMB).
According to Burken, et al. 2013, corn silage included in the diet at 45% on a DMB, compared with 15, 30 and 55% had the lowest cost of gain when corn was $3.50 and $5.00 per bushel and corn silage was priced at 8, 8.5 and 9 times the price of corn. When corn was priced at $6.50 per bushel, the lowest cost of gain inclusion rate of corn silage was 55% of the diets DMB. All these diets contained mWDG at 40% on a DMB. Increasing mWDG to 65% of the diet with 30% corn silage or removing mWDG completely with 45% corn silage was not as profitable. A comparison to corn stover was not made in this study.
The overall result is that corn silage is not only economical to add into the ration but is also a great way to secure some forage for this fall. So how much should you plan on cutting? A rule of thumb is that 6 pounds of corn silage will replace 1 pound of hay, 1 pound of corn and 4 pounds of water in a ration. The bulk density of corn silage can range from 35 to 55 pounds per cubic foot, wet; but would average around 45 pounds per cubic foot, wet. If you are sizing a bunker, a minimum of 6 inches of silage should be removed per day for minimal shrink and maximum quality. A typical feedlot steer will need 6 to 8 pounds to meet their roughage needs but as we have seen corn silage could be 2 to 3 times that level without significantly impacting performance. Growing calves can use 15 to 30 pounds in their ration and cows can utilize 10 to 30 pounds. Consult a nutritionist at Great Plains Livestock Consulting, Inc. for a customized feed budgets and recommendations.
Ki Fanning is a ruminate nutritionist with Great Plains Livestock Consulting (www.gplc-inc.com)