Most of the wet corn grain has been harvested in the Midwest and Northeast and stored as dried corn, propionic acid–treated wet corn and high-moisture corn.
Now the challenge is to utilize wet corn correctly in your dairy rations. Here are some tips for optimizing performance and health.
Shelled corn should be dried below 15% moisture to minimize the risk of mold development and heating. If you have stored corn on your farm that is above 15% moisture, keep an eye on these risks. If possible, feed it before the spring.
Artificially dried corn can be brittle and grind finer. Monitor grain particle size when processing on the farm, targeting 800 to 1100 microns. Wet corn that is frozen can also powder when grinding.
High-moisture corn (more than 26%) continues to change as starch becomes more fermentable in the rumen. Rumen acidosis and laminitis can occur if starch is more rapidly fermented in the rumen because of extended corn storage time. Lower levels of wet corn may be warranted, as may replacing some wet corn with dry corn or byproduct feed, such as corn gluten feed or hominy.
Ear rot in corn can lead to lower bushel weight (less than 56 lb.). The relation of corn energy value to lower bushel weight is somewhat in dispute. One guideline is to discount the energy content by 1 total digestible nutrient (TDN) percentage point per drop in bushel weight, starting at 50 lb. But some suggest starting at 54 lb., and others do not discount it at all.
Following the first guideline, if your bushel weight is 48 lb., for example, reduce TDN from 88% (normal corn grain) to 86% on a 100% dry matter base. If you want to evaluate this relationship, measure your bushel weight and conduct a starch and neutral
detergent fiber (NDF) analysis (corn grain is 72% starch and 9% NDF).
Keep monitoring mycotoxin levels if your corn had evidence of mold damage. One Midwestern testing lab reports that mycotoxins were present in corn samples it received, but at generally low levels (see first table). If wet grain is not dried or stored properly, the levels can increase. Continue to evaluate your animals' dry matter intake and manure scores as signs of damaged feed.
If you added propionic acid to your corn, use the second table to determine if the level added will hold corn in storage for the desired time.
Check your sources of corn byproduct feeds (such as corn gluten feed and distillers' grains) to be sure that wholesome corn was used when making ethanol. If the corn grain had mycotoxins or mold damage, the process of removing starch will have increased those levels.
In summary, your 2010 corn crop may be out of the field, but it's important to continue to monitor its quality and to realize that its feed value can increase (with wet corn) or decrease (with mold growth).
More on feeding wet, moldy corn:
Adjusting for 2009 corn
Molds & Toxins
Wet corn webinar