Careful planning, preparation can keep silage safe from spoilage
By LISA LIEBERMAN
For the Capital Press
Dairy farmers are looking for ways to save money and conserve resources, and that includes how they handle silage.
One thing many farmers can do, according to Noelia Silva-del-Rio, a dairy production medicine specialist with the University of California Agricultural Natural Resources, is to take a closer look at some of their silage and storage practices.
One of the most important parts of packing and storing silage is to make sure the pH is as low as possible and to keep out oxygen once the piles get packed.
"This time of year, the most important thing growers can do is to watch their piles and to keep them covered up in order to keep them from getting exposed to the air too much," Silva-del-Rio said. "The more they get exposed, the more likely the silage is to spoil."
One of the most important aspects of keeping a good silage pile is to pack it right in the first place, Silva-del-Rio said. This can be a complex undertaking. When it comes to harvesting forage, everyone has their own philosophy about the best dry matter weight.
"If you talk to the custom harvesters, they want to harvest it at 30 percent because it's easier to pack. Nutritionists would like to see it harvested it at 35 percent DM because you have a higher starch content and nutritional value," Silva-del-Rio said.
Harvesters like to cut the silage when it's wetter because it's easier to pack, but the drier the silage is, the more nutrition it has for the cows.
"So you have to compromise. That's why the general recommendation is that harvesters pick the forage somewhere between 30 and 35 percent," Silva-del-Rio said.
Silva-del-Rio, who is originally from Spain and has studied many Wisconsin dairies, said that one unique aspect about California silage piles is that they tend to get large. This can make it difficult to pack the forage well and to keep it properly covered, Silva-del-Rio said.
Large silage piles create a variety of problems. Ideally, dairymen want to keep the faces of their silage piles smooth to allow for as little air infiltration as possible.
In the Midwest, many dairymen have face shavers, which are special machines that keep the faces of the silage piles smooth. In California, most dairymen use front-end loaders to scoop from their silage piles. The mistake some dairymen make, though, is that instead of scooping from top to bottom, they scoop from bottom to top.
"Scooping from bottom to top is a bad way to do it because it allows more oxygen to enter the face of the pile and causes more spoilage," Silva-del-Rio said.
Another approach is to scoop the piles from side to side using the front loaders, Silva-del-Rio said.
"I told this to one worker ... and he didn't believe it could be done," Silva-del-Rio said. "But it can be done."
Silage preservation is all about preventing oxygen from getting into the piles in the first place, Silva-del-Rio said. The important thing to remember, though, is that oxygen is already going to be present in the piles from the day it's packed.
"When you bring forage in from the field, put it in the pile and pack it with a tractor and compress it, even if you do it perfectly, there's always oxygen," Silva-del-Rio said. "Therefore there are microorganisms in the plants that are going to come up and use the nutrients."
Most growers are happy if they have 8 to 10 percent losses of dry matter, but over 15 percent is generally unacceptable. Not packing, covering or removing silage correctly from the piles can add 3 percent loss, which can be easily avoided, Silva-del-Rio said.
"Three percent adds up and at this moment, every grower is trying to save as much money as he can," Silva-del-Rio said.
In terms of keeping the silage covered, many growers tend to throw plastic over the piles and use tires to weigh it down. This approach worked well in the past when feed was cheaper, but there are other steps growers can take to make sure their silage is better preserved.
One thing they can do is use an oxygen barrier, which is a transparent plastic that sticks to the silage. On top of that, farmers can use their regular plastic with the white side facing outward to reflect the sunlight.
Another step growers can take is to have enough tires covering their piles. The tires on the piles should touch each other.
Putting more tires on the silage piles isn't that much more expensive. It's just that it takes workers more time to take the tires on and off the piles when feeding the cows. This is why it's so important for growers to have good communication with their workers, Silva-del-Rio said.
Sometimes workers who are used to getting started at 3 a.m. to feed the cows and finishing up at 1 p.m. will make an extra silage pile for the next day, which they leave uncovered. These small piles get even more exposure to oxygen, further depleting nutrients.
Cows should be fed from the same silage pile from a single shaving off the face of a pile each day. Leaving feed exposed, even for just a couple of hours, is a problem. That's because when the silage is exposed to the air, yeast is multiplying and depleting nutrients, Silva-del-Rio said.