Genesis 30:37-43

Then Jacob took fresh rods of poplar and almond and plane trees, and peeled white stripes in them, exposing the white which was in the rods. He set the rods which he had peeled in front of the flocks in the gutters, even in the watering troughs, where the flocks came to drink; and they mated when they came to drink. So the flocks mated by the rods, and the flocks brought forth striped, speckled, and spotted. Jacob separated the lambs, and made the flocks face toward the striped and all the black in the flock of Laban; and he put his own herds apart, and did not put them with Laban’s flock. Moreover, whenever the stronger of the flock were mating, Jacob would place the rods in the sight of the flock in the gutters, so that they might mate by the rods; but when the flock was feeble, he did not put them in; so the feebler were Laban’s and the stronger Jacob’s. So the man became exceedingly prosperous, and had large flocks and female and male servants and camels and donkeys.