The U.S. dairy industry, the largest in the world, is under severe pressure as the dietary habits of Americans shift.

Borden Dairy Co. filed for bankruptcy protection, the second major U.S. dairy to do so in as many months. Borden produces nearly 500 million gallons of milk each year for groceries, schools and others. It employs 3,300 people and runs 12 plants across the U.S.

American refrigerators are increasingly stocked with juice, soda and milk substitutes made from soy or almonds. At the same time, protein bars, yogurts and other on-the-go breakfasts have replaced a morning bowl of cereal. That has hammered traditional milk producers like Borden, which was founded in 1857.

The amount of liquid milk consumed per capita in the U.S. has tumbled more than 40% since 1975. Americans drank around 24 gallons a year in 1996, according to government data. That dropped to 17 gallons in 2018.

"Despite our numerous achievements during the past 18 months, the company continues to be impacted by the rising cost of raw milk and market challenges facing the dairy industry," said Borden CEO Tony Sarsam in a prepared statement late Sunday. "These challenges have contributed to making our current level of debt unsustainable.

As milk consumption has fallen, dairy farms have closed their doors. In court filings, Borden says 2,730 U.S. dairy farms have gone out of business in the last 18 months alone. The remaining farms can command higher prices, but that has pinched Borden, which can't charge consumers more because of pressure from big competitors like Walmart. Walmart opened its own milk processing plant in Indiana in 2018.

Dean Foods, the nation's largest milk producer, filed for bankruptcy protection in November. Both dairies are based in Dallas.

Borden — whose smiling mascot Elsie the cow first appeared on milk cartons in the 1930s — says it will continue operations during its financial restructuring.