Farmers in the U.S. began producing silage as cattle feed in the late 19th century – during the early days of mechanized agriculture. Silage production continued to improve through the next century as silage became a feed of choice for many dairy farms due to its high feed quality and storage ability. Today, in most areas of the country, silage is the staple crop that the dairy ration is built around, and much research and innovation focus on how we make it better.
Improvements in silage production have led to silage that is more palatable, more digestible and has fewer mycotoxins – all leading to healthier cows that produce more milk.
In this article, Dan Kluth, a consultant with Standard Dairy Consultants, lends his expertise to the advancements in silage production over the last 30 years that he believes have made the biggest difference in silage quality.
First on the list of advancements in silage are the plastic-covered bunks that have become nearly synonymous with dairy country. However, bunk covers as an innovation have a relatively recent history.
“Bunk covers literally were not used 30 years ago – it wasn’t until the late '90s that you started seeing them. People realized that their piles were shrinking,” Kluth says. “I remember one dairy. They put their silage pile in and when I drove onto the dairy, I couldn't see over the pile to see their commodity shed. About six months later, I could see the top of their commodity shed. That pile had dropped 6 or 7 feet.”
At first, to combat that shrinkage, dairies started using a molasses blend to cover their piles. It was sprayed on when the pile was put up, but it wasn’t very sturdy, and as Kluth puts it, “the starlings loved it, birds would eat the heck out of it.” Today, bunks are covered with a double plastic layer. The first layer is a thin plastic that serves as an oxygen barrier, and the second is 5-mil plastic. This is followed by the standard layer of cut tires to hold the plastic down.
Next on the list is packing density. With the traditional tower silos of the mid-1900s, a high packing density was easy to achieve, but they lacked capacity and required too much labor and unloader maintenance. Pits and bunks became common, but packing density suffered. Over time, we’ve had to refine packing processes with new storage systems. Packed tighter and denser, the silage will have lower oxygen levels, so it will preserve faster and have less spoilage. Experts recommend that at minimum silage be 14 pounds of dry matter per cubic foot, but 15-16 pounds is better. Under the right conditions, 18 pounds is achievable, Kluth says.
During packing time, Kluth says a farm needs one packing tractor per chopper and another moving the silage.
“If you have two choppers, you should probably have three packing tractors,” Kluth says. “One moving the silage, the other two packing.”
The type of pile also makes a difference in density.
“The drive-over piles – rather than the steep, tall piles where you can't drive over the whole thing – are much better,” Kluth says. “With the tall piles, you're creating this mountain of silage. Inevitably, some loose silage falls over the edge and doesn't get packed.”
Inoculants began to play a big part in the improvement of silage as nutritionists and farmers considered the bacterial makeup of silage and how to speed up the fermentation process. Over the last decade, inoculants have become mainstream and the improvement in silage shows their impact. Lactobacillus (LAB) inoculants are the most popular, but other strains and additives are being tested and used.
“Lactobacillus inoculants are working on high lactic acid levels in the corn silage. The quicker, the better, because the less time corn silage is heating up, the less dry matter loss,” Kluth says. “Several years ago, I looked at a lab’s database results of all the silage being inoculated. Early on, the argument against inoculants was, ‘Corn will ferment easily anyway because of all the starch, so there is no real need to inoculate it.’ And, while that is true – corn does ferment easily – the data showed much higher levels of lactic acid in the inoculated than in noninoculated silage. You should inoculate if you want high lactic acid, which the cow utilizes well and keeps the silage stable and palatable. It steers fermentation quickly and efficiently.”
A major improvement in kernel processing in silage production came when corn chopping equipment improved through the research of farmer and inventor Marion Calmer. Calmer's patents helped equipment manufacturers make corn choppers better able to process the kernel during harvest.
“Kernel processing is interesting and is probably where we will see consistent improvement in silage,” Kluth says. “We send samples into a lab and run processing scores where they will screen the starch. A score of 50 to 70 is acceptable, but 10 years ago, many dairies were in that 30 to 40 range. At those levels, the cows can’t utilize corn to its full potential. We’d love to get that score to an 80, but probably the only way to get there is to slow down the chopper or increase chopper capacity.”
Research shows that for every 10-point improvement in processing scores, it’s a six-tenths of a pound in daily milk production improvement.
Silage face management is an improvement that has got a lot of attention as farmers work to hone in on feed management details. Proper face management aims to minimize silage exposure to oxygen by maintaining a smooth surface on the face of the silage pile. Kluth says there are three ways dairies do this: (1) using a mechanical face management implement, (2) using a silage rake and (3) using the loader bucket.
“Some feeders are good at facing silage with just a loader,” Kluth says. “It's easier to do when the silage is on asphalt, which is another thing we see dairies do to improve silage. With asphalt, a feeder can go along that face, shear off 3 or 4 inches of it with a loader bucket, and then come back along and pick it up. It is difficult to do that when the pile is on uneven dirt.”
Improvements from seed breeding
Finally, improvement in corn seed variety has been a major contributor to improved silage quality. And it’s where you can expect to see more improvement as seed companies hone in on specific and even regional traits of seeds.
“Seed companies continue to breed and test for better corn silage varieties,” Kluth says. “There are many things out there, but the ones that interest me the most are the seed with increased fiber digestibility, increased starch and corn better able to withstand a frost – so we don’t lose so much in the drydown. Also, especially out West, corn that is more drought resistant.”
Future of silage management
Finally, let’s consider the future of silage. What is the next big thing in silage production? Kluth expects the following to make a big difference as we move toward the next 30 years of silage production:
- Corn choppers with higher volume – More capacity means we can slow choppers down and work toward an 80 processing score.
- Continued improvement in silage corn seed and regionally specialized seed
- More widespread use of propionic acid to top piles before being covered
- Inoculants that help with specific situations – such as inoculants that stabilize the silage during transportation
- Replacement for cut tires as silage covers as we work towards better environmental stewardship
- More use of tech tools – such as infrared cameras, drones and probes to identify hot spots, check density and measure inventories
Erica Ramsey Louder is a freelance writer based in Idaho and was paid by Standard Dairy Consultants (SDC) to write this article. SDC provides dairy nutrition and management consulting, as well as innovative and customized solutions, to dairy producers throughout the U.S., with facilities in Idaho, Iowa, Pennsylvania, Texas and Washington.