Weather and growing conditions impact the yield and quality of forages fed to cattle. Despite all management efforts, there is an ever-present risk that adverse events will lead to a shortage of forages.
In May and June, we had a really good idea that the drought in the Dakotas would result in reduced forage availability west of the river. Throughout the Corn Belt, expected reductions in forage yield were spotty. In the Western U.S., the area under drought has continued to increase.
When forage shortages do occur, there are several alternatives that may help stretch supplies. In terms of alternatives for dairy cows, we’re looking at replacements for alfalfa and corn silage. For beef cows, we typically need alternatives to fescue pastures. Usually, it is easier to replace the forage equivalent of a beef cow diet rather than a dairy diet. The specifications are more modest, and it takes a lot less to fill the shortfall.
Consider feeding crop residues, such as corn stover, to beef cows. Corn stover refers to the plant material—including leaves, stalks and cobs—remaining in a field after it has been harvested. This is a pragmatic solution, and a common expectation is to budget an acre of corn stalks per month for each cow.
For dairy cows, however, feeding stover is not always the most viable option. Mid-gestation spring-calving cows typically have lower nutrition requirements, so they may be able to handle the lower forage quality of corn stalks. However, corn stover does not have adequate nutritional value for wet milk cows.
Treating and processing corn stover to improve its digestibility and/ or protein content can increase its potential as feed, particularly with dairy cows, but there are some significant limitations. Corn stover is lower in bulk density, nutrient value and digestibility. It is also relatively resistant to handling and grinding and has a high transportation cost per pound of total digestible nutrients.
When growing corn for grain, standability is important. Producers tend to select hybrids with a high lignin content in the stalk, which results in tougher plants that stand up better. From a corn grower’s perspective, this is desired. Lodged stalks can’t easily be picked up by the combine. As corn plants mature, the amount of lignin increases, while the digestible fiber—cellulose and hemicellulose—decreases.
The high lignin content of corn stover creates a challenge when fed to dairy cattle. The lignin acts as a barrier around the fiber, which hinders digestion by rumen bacteria. To address these challenges, mechanical chopping and chemical treatment of stover is often used to disrupt the lignin barrier, increasing the accessibility of cellulose and hemicellulose for rumen bacteria and resulting in improved overall digestibility.
Purdue University research found that using calcium hydroxide-treated corn stover can be a partial replacement for forage fed to dairy cattle without negatively impacting production. Calcium hydroxide is a common food ingredient used in a variety of applications, from pickling and preserving fruits and vegetables to adding calcium to fruit juices and baby formulas. It is formed by mixing water with calcium oxide derived from limestone.
At Purdue, researchers used corn stover that had been chopped, hydrated to 50% moisture, treated with 6.6% percent calcium hydroxide, combined with distiller’s grains, and fed at low rates. The study proved that the treated stover could replace up to a quarter of the alfalfa or corn silage fed to milking Holsteins while maintaining performance. That was not true, however, for the untreated stover.
Feeding calcium hydroxide-treated corn stover also resulted in more efficient feed-to-milk conversion compared to feeding untreated stover, and consequently income over feed costs were greater when treated corn stover was included in the diet.
Another point worth considering is the final calcium content of the treated stover when adding a calcium hydroxide treatment to feed. This might be helpful in some situations, such as if you’re needing to feed a restricted forage and high-grain diet to mature cattle. For dairy dry cows, however, it could result in excessive levels of calcium.
For beef or dairy producers looking to expand your forage supply, talk with your MFA agronomy or livestock consultants for more information on how to effectively use corn stover in your feeding program.
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