Genesis 30:40

And Jacob, &c.— After the success which attended his use of the pilled rods, he took care to keep what belonged to Laban separate from those lambs which, by agreement, belonged to himself; at the same time placing his ring-straked, &c. in the face or front of Laban's flock, that by that means also the flock might continue to bring forth party-coloured lambs. And now, finding his cattle increase, he began to be more curious about the breed; and therefore, Genesis 30:41 he placed the rods only before the stronger.