Question: In that case, it would be justified for him to claim, seeing as the creditor would then have been negligent in his guarding?

Answer: All the Gemara means is that the body of the ox is not Meshubad to the creditor as much as it is to the Nizak, who claims from its body.

Support: And that is how Rashi explains it at the beginning of 'Shor she'Nagach Arba'ah va'Chamishah' (later, Daf 36.).

Refuted Reason: The Gemara does not say this to teach us that he need not pay all of the potential improvement, in the event that it had not been damaged, since that is obvious ...

Refutation #1: ... because would one think that if it gored a small ox, that he must pay for the grown-up ox that it would have become and increased in value?

Refutation #2: Moreover, if that is what the Gemara needs to teach us, then how can the Gemara ask later 'If he fattened it, is it necessary to inform us that if the Nizak fattened it, he is Chayav to pay its value at the time of the damage'?

Authentic Reason: We must therefore explain the Gemara like Rashi's other (first) explanation.

Explanation #1: It speaks where the improvement does not exceed the expenses ...

Reason: ... because if it did, granted, the Gemara says in 'Chezkas ha'Batim' (Bava Basra, Daf 42b) that a partner is considered as if he had worked on the field with permission ...

Reason (cont.): ... nevertheless, however much a person would be willing to pay a fattener to fatten the ox, the Mazik is permitted to take, and the rest goes to the Nizak.

Question: In that case, why does the Gemara need to ask from the Reisha, when it could just as well have asked from the Seifa itself 'If he fattened it, why is it necessary to mention it?

Answer: The Seifa needs to be said, since we would have thought that now that, according to Rebbi Akiva, 'the ox belongs to the Nizak', when the Mazik subsequently fattens it, he has 'thrown his money on to the horn of a deer' (he loses it all) ...

Precedent: ... as in the case of a man who goes overseas and someone steps in and feeds his wife' (Kesuvos, Daf 107b).

Explanation #2: Alternatively, we can justifiably establish the case where the improvement exceeds the expenses ...

Implied Question: ... and when the Tana says 'Nosen ke'Sha'as ha'Nezek' ...

Answer: ... it is La'av Davka, and what he means is that he receives more than what he spent ...

Reason: ... because he is considered as having worked on the ox with permission.

Question: Why does the Gemara draw a distinction between improvement and depreciation? Why does it not distinguish by improvement itself and state that improvement that comes by itself is gauged by how much it is worth at the time when they go to Beis-Din.

Answer: Because in the Reisha, the Tana mentioned 'Shavach ve'Kichesh'.

Clarification: This Lashon is La'av Davka, and what it means is that the Mazik accepts upon himself half the depreciation ...

Conclusion: And according to the Maskana, he even takes half the Sh'vach.

Implied Question: Even though in the first Perek (Daf 10b), the Gemara learns it from "ve'ha'Meis Yih'yeh lo" ...

Answer: ... nevertheless the Pasul here is needed to teach us that he only pays Chatzi Nezek ...

Answer (cont.): ... because, as far as the Pasuk "ve'Chatzu es Kaspo" is concerned, we would have thought that sometimes more and sometimes less, as is evident shortly ...

Answer (cont.): ... where the Gemara asks 'If so, it transpires that, according to Rebbi Yehudah, he pays more than Chatzi Nezek?' and it answers that Rebbi Yehudah holds 'The depreciation that is caused by the animal's death, they divide in the live animal'.

Conclusion: So we see that from "ve'Gam es ha'Meis Yechetzun" we learn that he only has to pay Chatzi Nezek.

Question: But Rebbi Yehudah holds later (on Daf 45b) that the ox retains its Tzad Tamus even after it becomes a Mu'ad?

Answer: What the Gemara means is 'It transpires that the Tzad Tamus is more stringent than the Tzad Mu'adus' ...

Answer (cont.): And the Gemara then cites from the Beraisa of an ox that is worth a Manah ... ' - 'And if the Tzad Mu'ad, which is stringent, only pays for the damage (and no more), how much more so the Tzad Tamus, which is lenient!'

Refuted Explanation: This is not because the simple meaning of the Pasuk implies Chatzi Nezek, since that is not the case.

Authentic Explanation: So what the Gemara means is - that the Torah says "u'Machru", and Rebbi Yehudah cannot explain the Pasuk to mean that one must pay at any time more than Chatzi Nezek ...

Authentic Explanation (cont.): ... since we have heard that Rebbi Yehudah holds Chatzi Nezek, later in Perek Shor she'Nagach Arba'ah va'Chamishah (Daf 37a), when he says to the Chachamim 'On Shabbos he pays Nezek Shalem, and on weekdays, Chatzi Nezek'.

Clarification: The Gemara does not mention Tza'ar, Ripuy, Sheves and D'mei V'lados, since we already know them from the Mishnah in 'ha'Chovel (later, Daf 87a) ...

Implied Question: Even though it mentions Boshes there, too?

Answer: ... it nevertheless repeats it here in order to extrapolate that he has the same Din as his ox!' or vice-versa.

Precedent: And by the same token, the Tana needs to insert 'Shor she'Hidlik es ha'Gadish', as the Gemara explains ...

Reason: ... seeing as there is no other reason to insert it, since it is obvious that he is Chayav, because as far as the ox is concerned, what is the difference between Shabbos and a weekday.

Clarification (cont.): And because of the case of 'Hidlik ha'Gadish', where he is Chayav Misah, the Tana adds the case of 'Chaval be'Aviv ve'Imo'.

Conclusion: It is necessary however, to insert the case of 'Shoro she'Sima es Ein Avdo' ...

Reason: ... to teach us that even though he (the owner) would be Chayav, his ox is Patur ...

Reason (cont.): ... because there is no other Mishnah that teaches it.

Explanation #1: Rabeinu Shmuel explains that Rebbi Avahu holds like Rebbi Shimon, who holds 'Mekalkel ba'Chaburah Chayav', whilst Rebbi Yochanan holds like Rebbi Yehudah, who holds 'Mekalkel ba'Chaburah Patur'.

Explanation #1 (cont.): ... and what he needs for his dog or for ashes is considered not Mesaken, not Mekalkel, and is therefore Chayav even according to Rebbi Yochanan.

Question: In that case, why did he (Rebbi Yochanan) say 'Go and take your Beraisa outside!'? is it because he holds like Rebbi Yehudah that he may silence anyone who holds like Rebbi Shimon?

Precedent: ... since the Gemara asks a similar question in the first Perek of Chulin (on Daf 15a).

Explanation #2: It would therefore seem that Rebbi Avahu and Rebbi Yochanan are arguing according to Rebbi Shimon - that Rebbi Avahu holds like Rebbi Shimon, as the Gemara explain in Perek ha'Oreg (Shabbos, Daf 106a and Tosfos there, DH 'Chutz'), whereas Rebbi Yochanan holds that, even Rebbi Shimon requires a slight Tikun.

Explanation #2 (cont.): Though this would not be considered a Tikun to render him Chayav according to either Rebbi Yehudah or Rebbi Shimon by other Melachos ...

Reason: ... because it is not the norm to wound one friend it order to feed one's dog or to burn his haystack for the ashes.

Explanation #2 (concl.): ... and the reason that he is Chayav by Chovel and Mav'ir is because he learns it from Milah and the burning of a bas Kohen, as the Gemara explains there in Perek ha'Oreg.

Question: On what grounds does Rebbi Avahu declare him Chayav, even if he does not need it for his dog or for the ashes ...

Refuted Answer: ... bearing in mind that, even though Rebbi Shimon is Mechayev 'Mekalkel ba'Chaburah' ...

Refutation: ... one nevertheless requires 'Tzerichah le'Gufah', as is evident at the beginning of 'ha'Nechnakin' (Sanhedrin, Daf 84b and Tosfos there DH 'Ma'an, and in Perek Kol Kisvei, Shabbos, Daf 121a an in Perek K'lal Gadol, Ibid., Daf 75a, and Tosfos there DH 'T'fei' and in Perek Safek Achal, Kerisus, Daf 20b)?

Answer #1: The Ri explains that all of those Sugyos hold like Rebbi Yochanan ...

Answer #1 (cont.): ... and regarding the Sugyos in 'Safek Achal' and in 'Kol Kisvei', which are a Beraisa, one can say that that Tana holds like Rebbi Yehudah in one point (that 'Melachah she'Einah Tzerichah le'Gufah, Chayav') and like Rebbi Shimon, in the other.(that 'Mekalkel ba'Chaburah Chayav').