Taking haylage or corn silage from the entire face of a bunker silo and mixing it can help maximize ration consistency.

So says Bill Stone, a Cornell University extension dairy nutritionist and veterinarian. Uniform removal is beneficial because silage can vary considerably from the top to the bottom of a bunker, according to Stone.

“Feeding from just one area can negatively influence production or herd health,” he says.

“Often, feeders will obtain feed from a region of a silo,” he adds. “For example, when they're mixing a batch of feed, they'll take a front-end loader and drive into the pile and get the majority of feed from just one area. I wanted to know what influence that might have, on average, on the ration that's being prepared.”

Stone conducted research on nine dairies in central New York. He used a backhoe to collect samples from the upper, middle and lower sections of 11 corn silage and nine haylage bunker silos. Each sample was thoroughly mixed and analyzed for dry matter, crude protein, fiber and fermentation levels.

Among his findings:

  • Dry matter varied more in haylage than in corn silage, although there were examples of extreme variation in both types.

  • Although dry matters varied the most, fiber and crude protein levels varied considerably within some silos, too.

  • Fermentation types often varied greatly from the top, middle and bottom portions of the silo.

Why does silage vary so much from one part of a silo to another?

“With corn silage, the most likely reason is the producers had some fields that were different hybrids or maturity lengths, or some hybrids were grown in different soils, so maturity varied,” he explains.

“With haylage, it can be caused by the challenges producers face in getting the forage harvested at the desired dry matter percentage. Fiber and crude protein levels can also vary based on the types and amount of legumes and/or grasses grown.”

He recommends that feeders watch how they remove silage from bunker silos. “They could be delivering entirely different rations from one load of feed to the next if they're not careful.”

To prevent that, Stone says producers could benefit by using face shavers.

“Face shavers allow dairy producers or feeders to remove a uniform amount of feed across the height of the silo.”

That can be done with a loader bucket, too. “But it's more difficult — especially with haylage — to keep the face straight,” he says.

“If they want to refine the feeding process even further, they could then take all of that haylage or silage and put it in the mixer wagon for a few minutes, discharge it and feed from that one pile all day,” he adds.