By Jeff Lehmkuhler
It is hard to believe that it is near that time of year when corn will start to be harvested for silage. We have been fortunate in many areas of the region to receive timely precipitation providing for good corn stands. As the price of corn is still over $6/bushel on the spot market and the futures prices is in the mid 5’s, folks are asking about corn silage as an alternative feed this year.
When considering corn silage, first be sure that you are prepared. In many situations the harvest equipment may not be owned, and a custom harvest crew will come to chop and haul the silage. You need to get on their schedule and understand that weather and breakdowns can impact the harvest window for your corn crop. How do you plan to store the silage? For many beef operations, a silo bag is often the best choice. Again, the bagger will likely have to be rented and bags purchased. Be sure to get the bagger rented for sufficient time to fit the harvest window. Prepare the site for bags or drive over piles to ensure they drain well and water is diverted away from them. You don’t want to be driving through mud when trying to feed out silage from a pile or bag.
Corn will be ready to harvest when the whole plant moisture level is 62-65% or 35-38% dry matter. Fields will continue to dry down during the harvest and it is better to start harvest a bit wetter, so the last part of the field doesn’t get too dry. Corn that is less than 60% moisture should be considered for harvest as high moisture corn or allowed to dry and combined later. Corn harvested too dry simply doesn’t pack well and fermentation outcomes are less than ideal leading to poor quality feed.
Once corn is chopped and delivered to the storage area, ensure the highest quality of feed by obtaining the proper packing density. A packing density of 11-15 lb or on average 13 lb of dry matter per or 40-44 lb as-is per cubic foot would be targets. The fermentation process is mostly anaerobic. Therefore, packing reduces gaps where air is present in the silage and allows bacteria to quickly go from aerobic to anaerobic fermentation leading to greater lactic acid production leading to a lower pH for preserving the silage. Improperly packed silage will result in poor fermentation, higher pH, and greater yeast and mold growth.
When feeding out corn silage, the silage will be exposed to air and oxygen will be able to permeate into the silage at the exposed face. Oxygen exposure will begin an aerobic fermentation which can be felt as increased heat on the surface of the silage. This will lower the “shelf-life” or stability of the silage and impact intake and performance. In warm weather, it is recommended that 12” be removed daily from the exposed surface or face to minimize spoilage losses. During colder months, this may be reduced to six inches, but monitor the face for heating. In most instances, trenches, and drive over piles are made too wide for medium to small beef operations and excessive spoilage occurs. This is where a silo bag may be of value as they come in various diameters to better align with the feed out rate. Corn silage should be fed daily since secondary fermentation occurs immediately once exposed to oxygen. Additionally, listeria can grow in the presence of oxygen. Circling disease is the common term for listeriosis which may also be seen in partial facial paralysis. Cows that appear to not be able to swallow and their tongue is extended out as if chewing on the tongue are symptoms as well. It is important to manage silage feed out to minimize the risk of this disorder.
Corn silage is about 8% crude protein and will require supplementation when provided to lactating cows and growing calves. If used as the main feed source for growing calves combined with corn derived protein supplements such as distillers grains or corn gluten feed, be sure to supplement with calcium to meet their dietary calcium needs and reduce the risk of urinary calculi. Work with your Extension agent or nutritionist to develop feeding programs for your herd to ensure you offer a balanced diet that meets performance goals.
Source : osu.edu