Apparatus for controlling the formation of a sliver and comprising a card (10), a feeding device (11, 12) upstream of the card for feeding a lap to the card, a condenser (13) downstream of the card (10) to form a sliver, a set of measuring rollers (14, 15) arranged to receive the sliver and to monitor the parameters of the sliver and being arranged to respond to deviations of the sliver from a desired value, a feedback control arranged to respond to deviation monitoring (APD) by the measuring rollers (14, 15) and to make compensating adjustment in the speed of operation of the feeding device (11, 12), drafting rollers (16) arranged downstream of the measuring rollers (14, 15) and drive means for driving the drafting rollers at a predetermined speed relative to the speed of the measuring rollers (14, 15) to provide a required drafting ratio, a feed-forward control arranged to respond to deviation monitoring by the measuring rollers (14, 15) and coupled with the drive means of the drafting rollers to provide corresponding variation in speed of the drafting rollers, a device to monitor the ratio between peripheral distance (D1) travelled by the measuring rollers (14, 15) relative to the peripheral distance (D2) travelled by the drafting rollers (16) and for comparing the ratio with a desired value and where necessary issuing a deviation signal (DS), and means for applying the deviation signal as a further control to the drive means to vary the relative speed of the drafting rollers (16).