ARKANSAS BEST <ABZ> SEES LOWER FIRST QTR NET Arkansas Best Corp said its 1987 first quarter earnings will be significantly lower than fully diluted earnings of 22-1/2 cts per share in last year's first quarter. The company said pricing competition and lower traffic levels in the motor carrier industry hurt its first quarter results. However, the company said its furniture and tire operations are more profitable this year than last year. Arkansas Best also said that if the industry sustains the upcoming 2.9 pct motor carrier rate hike it will offset the Teamster labor increase scheduled for April 1. It said the labor increase then will be 3.2 pct for ABF Freight System, its largest unit.