Genesis 30:35-42

35That same day he removed all the male goats that were streaked or spotted, and all the speckled or spotted female goats (all that had white on them) and all the dark-colored lambs, and he placed them in the care of his sons.

36Then he put a three-day journey between himself and Jacob, while Jacob continued to tend the rest of Laban’s flocks. 37Jacob, however, took fresh-cut branches from poplar, almond and plane trees and made white stripes on them by peeling the bark and exposing the white inner wood of the branches. 38Then he placed the peeled branches in all the watering troughs, so that they would be directly in front of the flocks when they came to drink. When the flocks were in heat and came to drink, 39they mated in front of the branches. And they bore young that were streaked or speckled or spotted. 40Jacob set apart the young of the flock by themselves, but made the rest face the streaked and dark-colored animals that belonged to Laban. Thus he made separate flocks for himself and did not put them with Laban’s animals. 41Whenever the stronger females were in heat, Jacob would place the branches in the troughs in front of the animals so they would mate near the branches, 42but if the animals were weak, he would not place them there. So the weak animals went to Laban and the strong ones to Jacob.