Sforno on Genesis 30:35/ספורנו על בראשית ל׳:ל״ה

1ויסר ביום ההוא את התישים, after Lavan had agreed to Yaakov’s proposal he removed not only the females with such skin patterns as Yaakov had mentioned, etc., but also the males both young an mature ones. [His objective was to make it almost impossible for Yaakov to prosper by relying on genetic factors. Ed.]