Genesis 30:37-39

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.