It is known that the cattle in those parts did conceive and bring forth twice in a year, at spring and in autumn; and it is supposed that the stronger here mentioned, are such as joined in the spring, and the feeble they that joined in autumn.
Related Commentaries of Genesis 30:41
Genesis 30:41
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.