California dairyman Andy Rollin reduces air emissions and improves dry matter recovery by covering silage with an oxygen barrier film and plastic.
California dairies must cut silage emissions
Andy Rollin’s farm is one of 900 California dairies that must pay extra attention to silage management as a result of newly expanded air-quality laws.
Rule 4570 requires San Joaquin Valley dairies and other confined animal facilities (CAFs) to adopt additional management practices to reduce air emissions, not just from manure handling and storage but also from silage.
Officials with the San Joaquin Valley Air Pollution Control District revised the air-quality rule last October. The vast valley has some of the nation’s worst air quality.
The rule was amended after research conducted on California farms the past four years revealed that feed fermentation contributes more to smog-forming emissions than manure or cows.
Industry sources say it’s difficult to calculate the amended rule’s compliance costs since no two dairies operate the same and many already practice silage emission mitigation measures.
Rollin’s dairy is a good example. "We’ve already put a lot of the pieces together," says Rollin, who milks 2,000 cows with his father and brother near Riverdale, Calif. "Our management over the past four years has improved our silage quality and should help us comply with the amended rule."
Among its emission-cutting efforts, the Rollin dairy limits silage loss and shrinkage by compacting alfalfa, wheat and corn in high-density "rollover piles." The Rollins also harvest their feed at 64% to 66% moisture, giving them a 34% to 36% dry-matter level. "Higher than 70% results in poor fermentation and higher emissions," Rollin says.
In addition, the dairy uses an oxygen barrier film and plastic covering on silage to reduce spoilage. It also uses a quality inoculant that maximizes fermentation efficiency and improves the shelf life of open-face silage.
"We keep our silage pile as intact as possible," Rollin says. "The feeder shaves off only what we’re going to feed that day. In the end, the combination of all we’re doing will help us comply with the rule."
Rule 4570 offers a menu-driven system that allows producers to comply with both mandated and optional measures to cut down on emissions.
"The menu options are key because every dairy is set up differently," says Justin Gioletti, who milks 2,000 cows near Turlock, Calif. "Those choices have got to be there."
One option calls for dairies to bag their silage to curb emissions. "We’ve had 100% bagging for 10 years already," Gioletti says. "We have no silage piles at all. Last year, we started monitoring the packing density in our bags. We’ve made significant improvement in our feed quality."
Joey Airoso, who milks 2,500 cows near Pixley, Calif., says most dairy producers "don’t mind doing things that help the environment." He believes the revised rule balances environmental benefits along with improved feed operations.
"A lot of dairies are already doing the things required by 4570," Airoso says. "Twenty years ago, nobody covered their silage piles. Now, everybody’s starting to do it. There’s a cost, but also benefits: reducing shrink and keeping gases from being released."
Under Rule 4570, covering silage piles is mandatory. Dairies must increase silage bulk density and maintain an even silage face when removing silage from a pile or bunker. Many dairies already perform other requirements, such as pushing feed within 3' of a feed-lane fence and storing grain in a weather- proof storage structure or covering. Valley freestall dairies already pave their feed lanes at least 8' along corral sides.
- February 2011