American AgCredit has acquired a Petaluma company that provides crop insurance for grape growers and dairy farmers.

The Santa Rosa-based farm cooperative, the nation's sixth-largest with $6 billion in assets, has purchased Chris Maloney Crop Insurance Services. The agency was founded in 1999.

Financial terms were not disclosed.

American AgCredit previously acquired Fiorini & Squires Insurance Agency in Turlock in 2011. The latest expansion will allow the cooperative to offer insurance to farmers on the North Coast, Central Coast, Salinas, and Central Valley.

Dairy insurance provides farmers protection against the loss of gross margin based on the relationship between milk prices and feed costs. Such insurance is critical for farmers, said Ron Carli, president and CEO of American AgCredit.

"The ability to provide expanded services to agricultural producers is an important component of our business approach," Carli said in a statement.