37 And Jacob took him rods of green poplar, and of the hazel and chesnut tree; and pilled white strakes in them, and made the white appear which was in the rods.
38 And he set the rods which he had pilled before the flocks in the gutters in the watering troughs when the flocks came to drink, that they should conceive when they came to drink.
39 And the flocks conceived before the rods, and brought forth cattle ringstraked, speckled, and spotted.
40 And Jacob did separate the lambs, and set the faces of the flocks toward the ringstraked, and all the brown in the flock of Laban; and he put his own flocks by themselves, and put them not unto Laban’s cattle.
41 And it came to pass, whensoever the stronger cattle did conceive, that Jacob laid the rods before the eyes of the cattle in the gutters, that they might conceive among the rods.
42 But when the cattle were feeble, he put them not in: so the feebler were Laban’s, and the stronger Jacob’s.
43 And the man increased exceedingly, and had much cattle, and maidservants, and menservants, and camels, and asses.
K.J.V. Bible Text
We see beginning in Verse 37 of Chapter 30 that Jacob’s cunning was a match for Laban’s treachery. I’m not sure exactly what the description of placing the fresh-cut, striped branches in front of the cattle when they came to drink actually means. I’m not sure if this produced a holding pen for the animals while mating and for the newborn animals or had some other significance. However, it does seem that Jacob was practicing a little genetic selection by mating the strongest of his females with streaked or dark animals belonging to Laban. This enabled him to build a strong herd for himself and become very prosperous. As he has worked so long for Laban’s good rather than for his own, it seems this prosperity is well-deserved.