Genesis 30:40-42

Amplified Bible

⁴⁰ 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. ⁴¹ 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; ⁴² 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.