Research indicates that emissons from feed and silage piles are an issue when it comes to air quality, so California dairy farmers gathered in Modesto, Calif., Thursday to learn more about it. 

New regulations (Rule 4570) are intended to clean up the air in the central valley of California. Currently, this area fails air-quality standards for both ozone and particulate matter, both of which carry serious health risk to people living in the valley if levels are not reduced, according to officials.

The original thought process was to better manage manure, but now research indicates that emissions from feed and silage piles are a much bigger issue. This is addressed under the new air Rule 4570.

The regulations are not trying to limit you on the amount of silage you use, but they are concerned about the amount of open silage faces, notes Denise Mullinax with the California Dairy Quality Assurance Program.

Some of the measures to mitigate emissions are simple and are most likely practiced on the majority of dairy farms today, such as:

  • Feed according to National Research Council guidelines.
  • Push feed so that it is within three feet of feed lane fence within two hours of putting out the feed or use a feed trough or other feeding structure designed to maintain feed within reach of the cows.
  • Begin feeding total mixed rations within two hours of grinding and mixing rations.
  • Store grain in a weather proof storage structure.

The more challenging part of the regulation is how silage piles are built, how many piles a dairy has and how many they will be able to have open at once or feeding off of at once. But there are options available, such as using inoculants on all silage which could provide more flexibility in managing silage. Silage face management is also a key part of the new regulations.

Aside from silage management dairy producers must also comply with mitigation measures in the milking parlor, free-stall barn, corrals and manure management.

Air district officials said they are committed to assisting dairy farms in compliance. “We would rather have you be in compliance, work with you and reduce emissions than cite you for being non-compliant,” Sheraz Gill told audience members.

Regulations were met with some skepticism from audience members. But unlike other regulations dairy producers have had to face, these ones seem fairly straightforward and reasonable, says Annie Azevedo from Azevedo Dairy in Patterson, Calif. “There shouldn’t be too many operational changes, just more paperwork to file.”

To comply with Rule 4570, dairy farms have a menu-like option where they can select mitigation measures that fit their management styles. Dairy producers in California must turn in the individual game plans for meeting the regulation by April 21. In six months each dairy producer will receive a permit in the mail from the Air Board. Upon receipt of the permit dairy farms must start complying with the items they selected off the “menu,” for their operation. The first inspections will take place in about one-and-a-half years.

Air officials say they hope to achieve the anticipated reductions by that time.

Dairy is only one part of the equation in cleaning up the air in California, but it will play a significant role. Using the measures under Rule 4570, daily dairy volatile organic compound or VOC emissions in the valley will be reduced by 25 tons per day, an approximate reduction of 25 percent, down from 106 tons per day. VOC’s are important because they are a precursor to ozone, which is one of the issues.

More information on the new air quality regulations is available by going to: or to California Dairy Quality Assurance Program Web site.