Freight transporter Con-way ( CNW) cut its fourth-quarter earnings guidance, mostly as a result of a slowdown in shipping volume.The company said in a press release late Wednesday that it now expects to earn 72 cents to 76 cents a share from continuing operations, down from prior expectations of 81 cents to 87 cents a share a year earlier. "The slowdown we first experienced at Con-way Freight in the third quarter continued through the fourth quarter as the industry's traditional peak season surge did not materialize, and customer shipping volumes remained restrained," said Con-way President and CEO Douglas W. Stotlar. "Despite the tonnage decline, yield comparisons in the LTL business were positive and are expected to show a low single-digit increase for the quarter." The company said it expects a tonnage decline in the high single digits at its Con-way Freight unit, slightly more than originally expected. In addition, the company said earnings would be lower by $3.5 million, or 4 cents a share, from higher anticipated costs for vehicular casualty insurance expense, and by $1.5 million, or 2 cents a share, from a curtailment charge related to employee pension plan changes. Shares of Con-way were recently off 81 cents, or 1.8%, to $43.75 in after-hours trading.