Land O’Lakes Inc. said Wednesday that its quarterly net earnings dropped 16 percent from a year ago, “due mainly to higher spending on advertising and promotion of new products across the businesses.”

The Arden Hills-based cooperative earned $72 million in the first quarter on revenue of $4.2 billion. Revenue rose 8 percent over a year ago.

The results were in line with management’s expectations, the company said in a statement. “After reporting record sales and earnings in 2012, Land O’Lakes is building momentum to achieve even stronger earnings performance and accelerated growth,” said CEO Chris Policinski.

In the first quarter, Land O’Lakes introduced several major new dairy products, including a new deli cheese, a seasoned butter for cooking called Saute Express, and Koru brand creamery-style yogurt. Those products helped boost advertising spending, as did new Purina-branded feed for small animals made by the company’s feed division.

Also, Land O’Lakes boosted ad spending for its pesticide, herbicide and crop nutrients business, aiming to get its WinField brand more visibility in the marketplace.