Net profit fell by 47 percent to 3.19 billion kroner (429 million euros), and turnover by one percent to 17.42 billion.
A month of January "with weak winds" caused a lull in production, although February and March were "close to a normal wind year", it said.
Dong said earnings also suffered by comparison to a particularly strong year-earlier quarter when the renegotiation of gas purchase contracts and the sale of its gas distribution boosted income.
Dong shares swiftly ran into headwinds on the Copenhagen stock exchange in reaction Thursday, falling 1.9 percent in morning business.
The results for offshore wind, which the group considers its core business, deteriorated with a 19 percent decline in turnover and a 26 percent drop in gross operating income (EBITDA).
But Dong boosted its wind power production by 24 percent to 2.1 terawatt hours thanks to a rise in its capacity in mainly Germany and Britain.
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We are seeing significant momentum in the offshore wind industry, with innovation and notably reduced costs creating new market opportunities and an ever-stronger value chain. Competitive intensity is escalating," CEO Henrik Poulsen said in a statement.
The group welcomed the strong contribution of an activity it wants to spinoff, oil and gas, thanks to a "high and stable production" and a 70 percent cut in investments.
Poulsen reiterated the company still aims to sell this business this year, without giving any indication of a possible buyer.