What is the Chidush 'T'reifah Lo Heveisi Elecha... Genuvsi Yom u'Genuvsi Laylah'? A Shomer Sachar is liable for theft or loss!
Seforno: Yakov meant that even when Lavan demanded payment following an Ones (irrespective of whether it was torn by an animal, or stolen by a human by day or by an animal in the night), 1 he paid up. 2
Moshav Zekenim: I paid 3 even of Tereifah due to Ones. Genuvsi Yom u'Genuvsi Laylah is what became Tereifah through a wolf or lion.
Tosfos ha'Shalem (1, citing R. Yosef Karo): Yakov explains, you cannot say that you chased after me to pay for what became Tereifah or stolen, for I already paid!
Tosfos ha'Shalem (7, citing Chatzi Menasheh citing R. Yosef Angiloni): Hashem decreed that lions tear at night, and at the start of the day, until sunrise - "Laylah... ha'Kefirim Sho'agim la'Taref... Tizrach ha'Shemesh Ye'asefun". I stole from them their entitled prey during the day and at night.
What is "Achatenah"?
Rashi: I would remove [from my animals to pay for it].
Tosfos ha'Shalem (5): If a lion came to tear from the flock, I seized the prey from the lion, 1 (for I knew that you would demand that I pay you for it).
Tosfos ha'Shalem (6): There was a lion that used to eat from Lavan's flock every day, before I came (Bereishis Rabah 74:11). I "sinned" through depriving the lion of its sustenance. .