Dairy producers have been experimenting with harvesting corn as shredlage and snaplage. At the University of Wisconsin – Madison, Randy Shaver has been conducting feeding trials of these feedstuffs to see how they perform in the cow. He shared his results at the Vita Plus Dairy Summit, Dec. 5 in Merrillville, Indiana. Shredlage Currently shredlage processing rolls are only available on Claas choppers. These provide a longer theoretical length of cut of 1-¼ inches versus an average ¾-inch length of cut with a kernel processor.
“The real advantage of it is to get more effective fiber and good processing of the kernel,” Shaver said.
In the study, shredlage and conventional processed corn silage (KP) were sampled during feed-out from silage bags. In the Penn State Separator Box, the shredlage left 31.5 percent of material on the top screen, compared to 5.6 percent for KP. The percentage of starch to go through the coarse screen was 75 percent for shredlage versus 60 percent KP.
Shaver fed two experimental diets where everything in the diet remained the same, except one contained shredlage as 50 percent of the dry matter while the other used conventional corn silage for 50 percent of the dry matter.
The TMR sampled in the bunk by students had 15.6 percent of material on the top screen of the separator box for shredlage versus 3.5 percent for KP.
“We didn’t tear up the particle size through mixing process,” he commented.
During the feeding trial, the main effect they saw was a difference in milk production. While none of the cows produced poorly having averages of 95 to 100 pounds, they did see a 4-pound advantage after six to eight weeks of feeding shredlage.
Intakes were also higher at 1.3 pounds dry matter per cow on the shredlage diet.
“One of benefits for shredlage was better feed intake,” Shaver said. “We did see some improvement in fiber digestibility.”
Shredlage also picked up about 1.5 to 2 units of starch digestibility.
After the eight weeks, the bags had been fed so the trial did not extend further. He did mention that this year they harvested an entire bunker of each forage to test for packing density and do larger feeding trials.
He reported that there were no differences between forages in how they packed in the silage bags. While there is no data back yet on the bunkers, he said producers have told him that shredlage packs better because it is a flatter material.
“We’re going to learn a lot more from school of hard knocks,” he said, noting there are about 50 choppers out there equipped for shredlage that producers are trying on their own. Most of it was harvested this year, so more information will come out from January through April as it is fed.
Other notes he had on this study was that he did not see sorting, but if harvested coarser or drier, some might sort out. This particular study was on shredlage that was fairly wet and more research needs to be done on it harvested later. He is also considering harvesting BMR corn for shredlage to see how it would perform.
Snaplage
“Most nutritionists cringe at mention of snaplage or earlage,” Shaver said.
Previous forms of snaplage meant a lot of stalk, low starch and low energy. Plus, he added it was being handled in upright silos so the material would separate on the way in and on the way out.
With newer equipment – attaching a combine head to a modern self-propelled harvester –snaplage is coming in with 55 to 60 percent starch instead of the 40 to 45 percent starch of the past. Moisture of the finished product should be about 40 percent.
Just looking at harvested snaplage can be misguiding, he said. It really needs to be tested to show its nutritional value.
“Don’t write it off totally,” he said. “It has the advantage of speed of harvest. You can get it off the field earlier (than high moisture corn), and it is already rolled at harvest.”
Shaver did a feeding trial to compare snaplage to high moisture corn after each spent eight to 10 months in storage. The ammonia was 6 percent of crude protein in snaplage and 1.8 percent in high moisture corn.
Due to the flourier endosperm in snaplage it was better digested. Based on ammonia levels, the rate of digestion for snaplage was 26 percent per hour versus 19 percent per hour for high moisture corn.
In regards to milk production, milk yield and protein were similar. However, butterfat was at 3.7 percent when fed the high moisture corn diet and just 3.4 percent on the snaplage diet. When dry corn was added to the snaplage diet it did increase butterfat to 3.5 percent.
Compared to high moisture corn, which remained fairly consistent, the ammonia content of snaplage increased overtime in storage. Therefore it is important to assess and adjust for its changing levels of starch digestibility.
Starch digestibility
“We know dry matter, starch content and NDF,” Shaver said, but we need to find some way to assess starch digestibility.”
Ammonia nitrogen could be an indicator. He looked at corn silage analyses in three databases and found a lot of variation. The average ammonia nitrogen varies from 6 to 10 percent, almost none of which can be explained by dry matter content, he said.
Shaver also noted there is a lot of room for improvement across the industry in processing – either not using one or making sure it is set properly. Only 7 percent of the samples through Cumberland Valley Analytical Services were optimally processed. Forty-two percent of samples were inadequately processed.
“As crop consultants, nutritionists and producers we need to hold harvesters feet to the fire to see that this is done right,” he said. PD
Karen Lee
Editor
Progressive Dairyman magazine
