Genesis 30:38
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.
And he set the rods which he had pilled before the flocks,.... Opposite them, in the view of them:
in the gutters in the watering troughs, when the flocks came to drink; that is, in places of water, where troughs or vessels were made, into which the water ran convenient for the cattle to drink out of; and here he placed his party coloured rods right over against the flocks:
that they should conceive when they came to drink; as it was most likely they should when they were together at the water, and had refreshed themselves with it; and being "heated" {q}, as the word signifies, with a desire of copulation, might conceive in sight of the above rods; which were set to move upon their imagination at the time of their conception, in order to produce cattle of different colours; to which no doubt he was directed of God, and it had, through his blessing, the wished for success, as follows:
{q} hnmxy "incalescebant", Montanus, Vatablus, Drusius; "ut incalescerent", Junius & Tremellius.