Genesis 30:37-39

37Then Jacob 1took fresh rods of poplar and almond and plane trees, and peeled white stripes in them, exposing the white which was 2in the rods.

38He 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 3mated when they came to drink.

39So the flocks 4mated by the rods, and the flocks brought forth striped, speckled, and spotted.