Still looking for good data on corn silage hybrids? University silage trial results are now online for your viewing pleasure.
New York and Vermont’s trials — led by Cornell’s College of Agriculture and Life Sciences and University of Vermont Cooperative Extension — featured 90 entries from 16 seed brands planted in five locations: Albion, Aurora, Madrid and Willsboro, N.Y.; and Alburgh, Vt. Planting was done between May 5 and 21, and harvest was completed between Sept. 1 and 21, depending on location.
Penn State’s corn silage trials, which are done in cooperation with the Professional Dairy Managers of Pennsylvania, had 125 entries from 17 seed brands in 2020, a lower number considering entry fees were higher because researchers ran additional wet chemistry tests for NDFD30 and starch.
“Median yields were down this year for much of the state due to drought,” says Hanna Wells of the Professional Dairy Managers of Pennsylvania.
More short-season hybrids
“This was the largest entry since restarting the program in 2016,” says Joe Lawrence, the dairy forage systems specialist for Cornell Pro-Dairy, on the New York-Vermont trials. “Technically, it was 17 brands as Kings Agriseeds submitted two different brands they carry, King Fisher and Redtail. We were also pleased that there were more entries in our shorter-season category, as hybrids in this range are important in New York and New England.”
There were 38 entries in the 80- to 95-day relative maturity category and 52 entries in the 96- to 100-day RM category.
“Overall, yields were down slightly at most locations,” Lawrence says. They ranged from 16.5 tons to 19.8 tons in the 80- to 95-day trials, and 17.1 tons to 25.1 tons in the 96- to 110-day trials.
“Planting was quite timely as we had a relatively dry planting season," Lawrence says. "Early May was colder than normal, and we actually had a bit of a scare with cold snaps following planting at a few locations, but these cold snaps did not appear to have any long-term effects on the crop. We also had a great harvest season, with little challenges from rain or mud."
Yield, of course, isn’t the only factor researchers look at in these trials. “We really key in on fiber digestibility and how the growing conditions impact that,” Lawrence says.
In general, Lawrence says that uNDF240 — the amount of undigested neutral detergent fiber left in the rumen after 10 days — was quite low, which he says is expected during a year of low rainfall. Starch also is an important indicator of how the growing season went.
“Consistent with the record number of growing degree days and timely rain during ear fill, starch content was quite high," he says. "So, in general, our locations saw a slightly lower-yielding, highly digestible, high starch. Generally good news, the only challenge is with higher fiber digestibility. Cows will tend to eat more, and couple that with lower yields, and it could exacerbate potential inventory shortages."
Growing seasons are getting slightly longer, Lawrence says, as evidenced by the fact that many growers are tinkering with longer RMs in places such as the North Country. But this is risky, he says, because growers shouldn’t just look at total season length. They also need to account for more variable weather patterns — wetter springs, later frosts, and drier and hotter summers — that can create havoc with the growing season.
“So, we are really encouraging many farms to take a look at reducing RM slightly, which also adds emphasis to having better data on these shorter-season hybrids,” Lawrence says. “Another factor with shorter RM is making time for cover crop establishment after corn silage harvest. We continue to see that growing conditions [weather] can have as big or even a bigger impact on crop performance than genetics when it comes to some key forage quality metrics. But we also see that these differences vary quite a bit from year to year.”
“We discourage the approach of looking at our hybrid results tables and just picking the highest-performing hybrid at a particular location," Lawrence adds. "Not only is one location a small snapshot that may not tell the whole story on a hybrid, we know that companies only enter a small fraction of their hybrid portfolio into our trials. We strongly encourage using the trials as a way to calibrate to the growing season. The means from our locations give a good indicator of what was low, average or high for that growing season."
Pennsylvania trial results
The average yield for short-season varieties (85- to 105-day RM) in the Penn State trial was 18.9 tons, ranging from 17.7 tons in the 85- to 95-day group to 19.0 tons in the 96- to 105-day group.
The midseason varieties (100- to 111-day RM) averaged 14.0 tons, ranging from 13.6 tons in the 100- to 105-day group to 15.0 tons in the 106- to 111-day group.
The midseason southeast group (103- to 111-day RM) averaged 19.9 tons per acre.
The late-season silage trials (107- to 118-day RM) averaged 20.3 tons, ranging from 20.4 tons in the 107- to 114-day group to 20.3 tons in the 115- to 120-day group.
Seven locations were used for this year’s trials, Wells says, but due to drought, a few locations were dropped and backup locations were used instead.
“The dry weather was definitely a factor in overall crop performance this year," she says. "Yields were below average throughout much of the state. However, there were sites in Cambria and Bradford counties that did pretty well."
OMD index expands
All hybrids at all locations got wet chemistry testing for NDFD30 and starch for a new organic matter digestibility (OMD) index that was started last year. The OMD index represents the digestible portion of silage organic matter and is based on chemical analyses only.
“It does not predict dry matter intake or milk production, although numerous studies clearly show that digestibility of forage organic matter is directly related to lactation performance of dairy cows," Wells says. "The OMD index does not represent the absolute digestibility of silage organic matter, as this can be reliably determined only in experiments with live animals. But OMD is representative of the potentially digestible organic matter of the whole plant and can be used to compare silage hybrids.
“Simply put, the higher the OMD value, the higher the overall expected digestibility of the silage," she adds. "OMD reflects the digestibility of key nutrients within the entire plant."