Gittin 42B

וחצי כופר ליורשיו. אמאי? הכי נמי לימא: יום של רבו ⁠– לרבו, יום של עצמו ⁠– לעצמו! שאני הכא דקא כליא קרנא.

and half of a ransom, i.e., half of the value of the deceased, to his heirs. According to what was stated earlier, why is this the halakha? So too, in this case let us say: If the ox killed him on the day of his master, then the full penalty of 30 shekels is paid to his master, but if it killed him on his own day, then the full ransom is paid to the slave himself, i.e., his heirs. The Talmud answers: This is different, for the principal is consumed. Since the slave is dead, even if the goring occurred on a day that he was working for himself, there is a permanent loss to the master, who is therefore entitled to be paid half of a penalty.

ואלא היכי דמי דלא קא כליא קרנא? כגון שהכהו על ידו, וצמתה ידו וסופה לחזור.

The Talmud asks: Rather, what are the circumstances when the principal is not consumed and the reimbursement is paid based on the day on which the ox gored the slave? The Talmud explains: It is a case where an ox struck him on his hand and his hand withered, but it will eventually return and heal. In this case, there is no permanent loss.

הניחא לאביי, דאמר: נותן לו שבת גדולה, ושבת קטנה ⁠– שפיר.

The Talmud challenges: This works out well according to the opinion of Abaye, who says: If one injures another and the injury causes him temporary paralysis, then he gives him the value of the major loss of livelihood, i.e., the decrease in his value, as measured by his price on the slave market, due to his temporary paralysis. And he also gives him the value of the minor loss of livelihood, i.e., the actual wages he lost during the time he was injured. This works out well, as in this case, the owner of the ox would have to pay the major loss of livelihood.