Genesis 30:38,41; (DRB):
38 And he put them in the troughs, where the water was poured out: that when the flocks should come to drink, they might have the rods before their eyes, and in the sight of them might conceive.
41 So when the ewes went first to ram, Jacob put the rods in the roughs of water before the eyes of the rams, and of the ewes, that they might conceive while they were looking upon them:
Is the story of conceiving of the rams to be taken literally?
Jacob did many things that did not accord with the divine plan for his life. The Bible simply lists and records these as they are without any hint of endorsement.
I take the story of Jacob's animal breeding, and the obvious superstitions associated with it, as simply the way the ancients thought about these things. I read the story literally but do not understand this as a statement of how we should breed today.
Similarly, I do not understand Abraham's actions with Hagar as any kind of endorsement for such beliefs and behaviour.
There are numerous examples of what the OT characters did that are NOT intended as a model for our thought and behaviour.
Indeed, the Pulpit commentary observes for Gen 30:39 -
Verse 39. - And the flocks conceived (ut supra) before the rods, and brought forth cattle ringstraked, speckled, and spotted. The fact is said to have been frequently observed that, particularly in the case of sheep, whatever fixes their attention in copulation is marked upon the young. That Jacob believed in the efficacy of the artifice he adopted is apparent; but the multiplication of Parti-colored animals it will be safer to ascribe to Divine blessing than to human craft.
At the time it was believed that the things a person or animal is thinking about at the moment of conception could effect the appearance of the child. See Seforno to Genesis 30:38. This is called "maternal imprinting." This belief was very common in the ancient world and still prevalent in Talmudic times. See this article on the subject from Talmudology.
However, in the next chapter in Genesis (31:10-12) it is revealed to Jacob prophetically that it was not his attempts at maternal imprinting that succeeded in causing the birth of the spotted and speckled sheep but rather Divine intervention:
וַיְהִ֗י בְּעֵת֙ יַחֵ֣ם הַצֹּ֔אן וָאֶשָּׂ֥א עֵינַ֛י וָאֵ֖רֶא בַּחֲל֑וֹם וְהִנֵּ֤ה הָֽעַתֻּדִים֙ הָעֹלִ֣ים עַל־הַצֹּ֔אן עֲקֻדִּ֥ים נְקֻדִּ֖ים וּבְרֻדִּֽים׃
“Once, at the mating time of the flocks, I had a dream in which I saw that the he-goats mating with the flock were streaked, speckled, and mottled.
וַיֹּ֨אמֶר אֵלַ֜י מַלְאַ֧ךְ הָאֱלֹהִ֛ים בַּחֲל֖וֹם יַֽעֲקֹ֑ב וָאֹמַ֖ר הִנֵּֽנִי׃
And in the dream an angel of God said to me, ‘Jacob!’ ‘Here,’ I answered.
וַיֹּ֗אמֶר שָׂא־נָ֨א עֵינֶ֤יךָ וּרְאֵה֙ כָּל־הָֽעַתֻּדִים֙ הָעֹלִ֣ים עַל־הַצֹּ֔אן עֲקֻדִּ֥ים נְקֻדִּ֖ים וּבְרֻדִּ֑ים כִּ֣י רָאִ֔יתִי אֵ֛ת כָּל־אֲשֶׁ֥ר לָבָ֖ן עֹ֥שֶׂה לָּֽךְ׃
And he said, ‘Note well that all the he-goats which are mating with the flock are streaked, speckled, and mottled; for I have noted all that Laban has been doing to you.
And Rashi on Genesis 31:10 quotes the Midrash that although Laban had separated the colored sheep from the flock, angels were transporting them to Jacob's flock to mate with the female sheep.
Thus, it appears from the simple meaning of the verses that Jacob attempted to use maternal imprinting as a technique to get his wages. But in reality it was not the maternal imprinting that was successful but a miracle.
