The widely diversified LTV Corp. rolled up a $25-million loss in the first quarter, mostly from its steel operations that were hard hit by the coal strike.

Paul Thayer, chairman and chief executive, said the firm's J&L steel unit had an operating loss of $15.5 million during the period, 60 percent of the total $25-million deficit LTV reported.

He said while the food and aerospace divisions had operating income for the period, "the prolonged coal strike . . . penalized our steel operations by approximately $25 million." The strike, which started in December, was in effect through most of the first quarter.

The company's overall deficit for the first quarter compared with a $3.6-million deficit in the 1977 period despite $12.3-million tax credit. In the 1978 quarter the company reported a $2.3-million credit from sale of its Steel Service Center division.

Sales in the latest period rose to $1.24 billion from $1.11 billion.

The company announced that it has deferred setting a date for the annual meeting pending a Justice Department decision in its proposed merger with Lykes Corp., expected soon.

General Dynamics Corp., the aerospace, marine and mining combine, earned $1.86 a share in the first quarter, up from $1.73 a year ago, on a rise in sales to $682.1 million from $678.4 million.

However, the main cause of the gain was an 18-cents a share windfall in the collection of $1.9 million debt from Federal Express Corp. that previously had been written off.

This offset a substantial loss in General Dynamics coal mining operations. The shipbuilding and aerospace divisions had good profits for the quarter, the company said.

David S. Lewis, chairman and chief executive officer, told shareholders at the company's annual meeting said further discussions are planned with officials of the Navy in General Dynamics' dispute involving cost overruns in the production of 18 SSN 688-class attack submarines. The company has filed claims totaling $544 million to cover the added costs, Lewis said.