Genesis 30:37-43

Then Jacob took branches of fresh poplar and almond and plane trees, and peeled white stripes in them, exposing the white in the branches. Then he set the branches which he had peeled in front of the flocks in the watering troughs, where the flocks came to drink; and they mated and conceived when they came to drink. So the flocks mated and conceived by the branches, and the flocks gave birth to streaked, speckled, and spotted offspring. Jacob separated the lambs, and [as he had done with the peeled branches] he made the flocks face toward the streaked and all the dark or black in the [new] flock of Laban; and he put his own herds apart by themselves and did not put them [where they could breed] with Laban’s flock. Furthermore, whenever the stronger [animals] of the flocks were breeding, Jacob would place the branches in the sight of the flock in the watering troughs, so that they would mate and conceive among the branches; but when the flock was sickly, he did not put the branches there; so the sicker [animals] were Laban’s and the stronger Jacob’s. So Jacob became exceedingly prosperous, and had large flocks [of sheep and goats], and female and male servants, and camels and donkeys.