Are you ready for corn silage harvest?
That is the question the Central New York Dairy, CCE Dairy & Field Crops specialists Kevin Ganoe and David Balbian asked attendees at recent corn silage pre-harvest meetings that were hosted by several farms around Central New York.
Ganoe and Balbian spoke to attendees about determining corn maturation.
Generally 60 days is the approximate time that it takes for corn to mature from silking to maturity, however, Ganoe pointed out that growing degree days are important to consider in your calculations, and this calculation will differ for hybrids.
“So, how do you decide when to chop?” asked Balbian. “Milk line used to be the guide line, until we had such a big variation in feed and people found out that there was quite a range of moisture content at a given milk line.”
Balbian said although milk line can be used as a gauge to determine when to begin monitoring whole plant moisture, it should not be used as an indicator of chopping, due to dry matter content of the whole plant.
Using one-half milk line is the point to start checking for whole plant moisture.
“Whole plant dry matter may be higher under dry soil conditions at the same stage of plant and kernel maturity.”
Taking samples from several plants at different locations in the field will give you a better idea of true moisture content.
Ganoe and Balbian advise using a Koster tester or a microwave oven, noting that a Koster tester reading will read 1–2 points higher than the actual dry matter.
Seventy percent moisture is generally a good target for beginning your harvest, but keep in mind that 32–38 percent dry matter is the desired range.
Serious consideration should be given to silage storage and bunk storage was discussed in the meeting.
“You should know how much weight you need to pack your bunk!”
Bunk silos need to be kept covered to assure feed losses are kept at a minimum.
“You don’t see it very often anymore,” said Balbian. “But, you used to see bunk silos kept uncovered.”
Efficient fermentation and conversion of carbohydrates will benefit your cows and show up in production and profit.
If harvested at greater than 40 percent moisture content, there is a greater risk of molds and possibly a decrease in milk production. Higher moisture content also makes packing in the bunk silo less efficient.
Lengths of chopped silage was also discussed.
Balbian demonstrated how a Penn State Forage Particle Separator works and explained why size of the silage is important for digestion. Three-quarter inch is the recommended length for best digestion, with one-half inch recommended for dry matter over 40 percent moisture.
Kernel development and processing also affects milk production, and can increase starch and fiber digestibility. “Average milk production response in 22 studies was 1.1 pounds,” Balbian confirmed.
Corn silage processing scores and using a Ro Tap Sieve Shaker to determine dried corn silage size were discussed.
“Poorly processed corn silage will lead to lower rumen starch degradation and a lower total tract digestibility.”
Balbian reminded attendees to check their chopper rollers and replace them as required.
Ganoe spoke to attendees about corn disease and leaf blights, showing samples to attendees.
“Northern Corn Leaf Blight lesions are grayish-tan, long and oval shaped,” said Ganoe. “The lesions can be very long. Hybrids can be less resistant.”
Gray Leaf Spot was also discussed.
Early symptoms of this disease are yellowish lesions with a slight watery outline. As the disease progresses, lesions turn brown and become rectangular shaped. Lesion may grow to be 3 to 4 inches long and about 1/8 inch wide. It is possible for Gray leaf spot to reduce corn yield from 5 to 40 bushels per acre.
Scout fields for these diseases at tasseling. When lesions on leaves at or above corn ears exceed 5 percent of plant leaves, consider using a fungicide. However, when lesions develop after tasseling, economic benefits from using fungicides are less.
Both diseases will overwinter on corn debris. Spores are transmitted by wind and rain. Crop rotation is a recommended and effective method for controlling these diseases.
“Doing all the little things right really makes a big difference in what your cows will get out of the corn silage you harvest,” said Balbian. “The proper moisture content, excellent processing, good packing and covering all make a big difference. You need to monitor all of these things when you harvest. Don’t wait until you’re done harvesting to see how you’ve done.”