In Florida, Luiz Ferraretto, assistant professor of livestock nutrition at the University of Florida, said much of Florida’s spring silage harvest is now complete, and it yielded a very good crop. However, many parts of the Midwest had a very different experience with corn planting this year. Moving toward harvest season, it’ll be important to make the most out of your corn silage.
“If farmers had a severe delay when they planted corn and didn’t change to a shorter season hybrid, the crops will take the usual amount of time to grow, which does change every year because of temperature, rain and other related factors,” Ferraretto said. “If they need to harvest late, it’s quite possible to get some very cold temperatures, and some corn silage may enter the silo, not necessarily frozen, but its temperature will be very low. Temperature is very important for bacteria to start the fermentation process, and a change in temperature can completely change the bacteria profile and drastically reduce fermentation.”
If you have a lot of silage entering the silo frozen or near-frozen, it will reduce the nutritive value. If the temperature of corn silage stays low for too long, it reduces its ability to ferment or may not be able to start the fermentation process at all. It’s important to discuss this with your nutritionist so the ration can be monitored and modified as needed.
Monitor Moisture Level
Go to the field often and track moisture or dry matter (DM) to ensure you’re harvesting at the correct maturity in order to avoid harvesting too wet or too dry. One way to do that is watching the kernel milkline, but Ferraretto said given the current conditions, the kernel milkline might not be a good indicator because plants may not be growing at the same rate they normally would, given the late planting conditions of the corn crop, he explained.
“I usually suggest using both kernel milkline as well as the moisture or DM content,” he said. “It may be even more important this year since the kernel-to-plant ratio may be different than a typical year.”
If corn silage is too wet when harvested, the result is lost material due to seepage. The extra water in the crop will move to the bottom, leaving the silo as effluent and removing some of the nutrients. Alternatively, if the crop is too dry, it can impair fermentation.
Tips to Minimize Losses at Harvest
Eliminate air – the amount of air entrapped in the silo can reduce fermentation, so it's very important to have enough equipment to pack the silo fast but also make sure density is adequate.
Speed - the amount of time spent filling the silo is also very important to successful fermentation. The quicker the silo is sealed the better because it allows less air to accumulate. No matter how well you pack, the longer it takes to finish the job, the more fermentation from aerobic microorganisms occurs. The goal is to make sure substrates are available for the anaerobic microorganisms.
Pack and seal - fill the silo in a timely manner, while ensuring corn silage is packed to the correct density. Then, seal the silo properly to avoid any further air entrance. This will limit losses related to deterioration during anaerobic fermentation. Know the number of trucks coming to the silo, so you are ready to pack small layers of silage as they are unloaded. Avoid having several trucks waiting in line to unload.
Inoculant - use a microbial inoculant to speed up the fermentation process, keeping in mind the impact cold temperatures can have.
Chop size - the amount of air in the silo is impacted by the porosity of the corn silage. Ferraretto recommends a 3/4-inch chop setting in the Midwest and 3/4-inch- to 1-inch setting in the Southeast.
One of the keys to minimizing losses is to plan for harvest in advance and make sure you have enough tractors to pack.
“Sometimes people are in a hurry, and they end up using the same tractor in the field and to pack. Be careful with that, as you can bring a lot of mud and/or sand into the silo,” Ferraretto noted. “With the mud contamination, it can bring molds and fungi, which may lead to poor fermentation and mycotoxins.”
Dairy Herd Management