It’s all about timing. The key to silage quality is cutting at the optimum stage of maturity.
“If it doesn't get harvested at the right time, the fiber content increases and the lignin component of the fiber increases,” said Professor Randy Shaver, professor and extension dairy nutritionist at the University of Wisconsin-Madison. “It becomes less digestible, so the cow cannot eat as much and production goes down.”
For alfalfa, the best time to cut is the late bud stage of maturity. For grass, it's at the boot stage or just after the boot stage which will optimize the quality from the standpoint of low neutral detergent fiber (NDF). This should also allow for low-lignin and high-fiber digestibility which will enhance forage intake and production.
Also related to timing, have your equipment prepped and set to go, and keep open the lines of communication with your custom harvester so they can cut at the right time.
Another consideration is chopping at the proper moisture content, which is typically around 40% dry matter, 60% moisture. Again timing comes into play – you don't want it too wet, but you don't want it too dry.
“If it's too wet, less than 35% dry matter, it increases the risk of having clostridial spoilage or high ammonia or high butyric acid silage. If it gets too dry, more than 45% dry matter, then it’ll increase the risk of packing problems; and also field losses can increase,” Shaver said.
“Once you've cut it at the right stage of maturity, then let it wilt in the field to that narrow window of 35%-45% dry matter with an average of about 40% being optimum,” he said.
“Typically, we talk about a theoretical length of cut setting on a chopper,” he said. “For hay crop silage that would typically be about [a] ½” theoretical length of cut.”
Inoculants are often applied as liquids on the chopper at the time of chopping, so it’s important to ensure that the application equipment is set up and working properly.
“It’s always good to review the correct application rate with your supplier, because inoculants are important for minimizing the risk of a bad fermentation happening, helping to improve silage quality and reducing losses in the silo,” Shaver said.
Once the chopped silage is delivered to the silo, it’s time to pack, pack, pack! That comes down to having enough packing tractors on-hand to keep up with the rate of delivery from the field. Then its continual packing with enough weight on the tractors to get a good packing density of 45 lb. per ft³ or higher.
“Along with packing, it basically gets down to trying to fill that silo as rapidly as you can and then covering the silo properly and right away,” he said. “More and more people are going with the oxygen barrier type plastic with multiple layers, trying to minimize surface spoilage. And then getting the tires on quickly to hold the plastic down.”
On a final note, don’t forget about safety. Serious accidents can happen while filling the silo. Think through the danger points of the process and talk about them with your employees or family members who are helping you.
“Everybody's in a hurry. You're trying to fight against weather and against the advancing stage of maturity. You're trying to get the silo full and packed so you can cover it. There [are] a lot of moving parts, both equipment and people, particularly in these bigger operations. Have a good plan in place to ensure that it's a safe process for everyone involved,” Dr. Shaver said.