I would like to explain what i think is the answer of Rav Shach concerning a certain difficult Rambam. The Rambam writes in laws of Tmura chap4 law 9 that the baby born from a animal with a blemish is like the baby born by an animal with no blemish and it can be sacrificed for whatever it is meant for. this seems to be opposed to the Gemara in tmura page 17b from Shmuel who brings a verse that says the baby born from an animal with blemish is considered for for the altar in the opinion of R Elezar for R Elazar holds even a baby born from a female sanctified to be a burnt offering can be brought as a sacrifice. But Bar Pada said that verse is meant to tell us that the animal born from a female that has a blemish must go into the field to pasture until it gets a blemish and then is sold and with that money a new sacrifice is bought. {The Rambam writes that even the sages hold the animal can be sacrificed. This seems in contradiction to both Shmuel and Bar Pada.} I think Rav Shach intends to answer this seeming contradiction thus. The Gemara is referring to a case when the animal had a blemish and after that it was sanctified. However, the Rambam is referring to a case of when the animal was sanctified and then received a blemish. [The difference is in the latter case; the holiness was perfect and only later came the blemish. This difference seems clear in itself except for the fact that the Rambam did not write anything that could indicate that this is his intension.] This would go along well with the general approach of Rav Shach in his understanding of the Rambam that in general a baby goes by the mother when the type of sanctification itself is pushed off. And having a blemish seems to fit into this kind of “pushed off holiness”. For Rav Shach makes a distinction between holiness that is pushed off as in a case of a female that is sanctified to be a burn offering as opposed to a case of two partners that have an animal that one sanctified.-----------------------------------I would like to explain what i think is the answer of רב שך concerning a certain difficult רמב’’ם. The רמב’’ם writes in laws of תמורה פרק ד' law ט' that the וולד born from a animal with a מום is like the וולד born by an animal with no מום (תמימה)and it can be sacrificed for whatever it is meant for. this seems to be opposed to the גמרא in תמורה page י''ז ע''ב from שמואל who brings a verse that says the וולד born from an animal with מום is considered for for the altar in the opinion of ר’ אלעזר for ר’ אלעזר holds even a וולד born from a female sanctified to be a עולה can be brought as a sacrifice. But בר פדא said that verse is meant to tell us לכל הדעות that the animal born from a female that has a מום must go into the field to pasture until it gets a מום and then is sold and with that money a new sacrifice is bought. {The רמב’’ם writes that even the חכמים hold the animal can be sacrificed. This seems in contradiction to both שמואל and בר פדא.} I think רב שך intends to answer this seeming contradiction thus. The גמרא is referring to a case when the animal had a מום and after that it was sanctified. However, the רמב’’ם is referring to a case of when the animal was sanctified and then received a מום. [The difference is in the latter case; the holiness was perfect, and only later came the מום. This difference seems clear in itself except for the fact that the רמב''ם did not write anything that could indicate that this is his intension.] This would go along well with the general approach of רב שך in his understanding of the רמב’’ם that in general a וולד goes by the mother when the type of sanctification itself is pushed off. And having a מום seems to fit into this kind of “pushed off holiness”. For רב שך makes a distinction between holiness that is pushed off as in a case of a female that is sanctified to be a burn offering as opposed to a case of two partners that have an animal that one sanctified.