Corn silage trials track nutrients, pest damage

by Deborah Jeanne Sergeant

WATERLOO, NY — New York and Vermont’s Corn silage trials are about more than yield data, according to Joe Lawrence, dairy forage systems specialist for Cornell’s Department of Animal Science. He presented findings at the recent 2018 Corn Congress from a collaborative effort of Cornell University PRO-DAIRY Department of Animal Science and Department of Plant Breeding & Genetics, plus the University of Vermont.

Lawrence said the indicators of corn silage quality for high producing dairy herds include low neutral detergent fiber, low lignin, and low undigested fiber but high total track neutral detergent fiber, starch and milk per ton.

Lawrence explained that undigested fiber provides no nutrients but just “gut fill” that displaces nutrients the cow needs.

“It decreases production,” Lawrence added. “We can’t explain all feed refusals, but we can talk about forages with undigested neutral detergent fiber.”

The trials took place in the 2017 season on farms in Alburgh, VT, and Albion and Willsboro, NY, which had 80 to 95-day relative maturity hybrids. At farms in Aurora and Madrid, NY and Alburgh, VT, researchers planted 96 to 110-day relative maturity corn. Seventy-three hybrids entered the trial.

The researchers found that poorly drained soil produces corn with lower digestibility.

“It’s not just whether it drains, but about the content of the soil,” Lawrence said. “There’s a strong correlation between increased rainfall in July and decreased neutral detergent fiber digestibility. Different things throughout the growing season signals responses in plants and that affects digestibility.”

He encouraged farmers to consider their corn’s nutritional quality as a way to ensure the herd obtains the nutrient it needs, especially if the hay offered is sub-par.

“There’s a very strong relationship between soil type and NDF digestibility at all time points,” Lawrence said. “Due to limited sample size, we cannot tell if the interaction between hybrid and soil type and NDF digestibility. From available data, no relationship exists through. Does this mean there are certain soil types that should not be used for corn silage? Or are there agronomic factors we can address to improve NDF digestibility?”

Lawrence said comparing data is relative, as it depends upon to what the data are compared.

“Picking the best hybrid for your farm is not a competition to pick the highest ranked hybrid,” Lawrence said.

He encouraged farmers to contemplate how consistently the hybrid performs across locations, how well it performs under conditions similar to the farm, including soil type and length of the growing season.

“What factors impact predicted milk yields the most?” Lawrence said. “Digestible fiber. What factors match your needs and feeding program? Yield, starch, and digestible fiber.”

He said by selecting the factors that matter most to the farm and then by matching those factors to the appropriate hybrid, farmers can find the right product and not “just by picking the top-rated products.”

The Corn Silage Trial Program included western bean cutworm and mycotoxin screening. In Madris and Aurora, NY, the researchers assessed plots for ear damage prior to harvest and at harvest, collected samples for mycotoxin screening. Three toxins showed up in trials, vomitoxin, 15-acetyl DON, and zearalenone.

“We are seeing more in the north part of the state,” Lawrence said. “At both locations, we had traps. Northern New York had definitely more than Aurora.”

The researchers found no clear link between western bean cutworm damage and mycotoxin development. They believe that the pests may have entered the ears through the silk without damaging the leaves. Rain may have helped enable this route for the cutworms.

“With a drier year, that could change,” Lawrence said.

The Madrid site experienced quite a bit of eye spot.

“Some were loaded with eye spot right next to some without,” Lawrence said. “It speaks to the genetic differences there.”

He believes monitoring cutworms over additional growing seasons will provide more insights into the formation of mycotoxin.

2018-01-19T12:04:38+00:00January 19th, 2018|Eastern Edition, New England Farm Weekly, Western Edition|0 Comments

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