Not all cattle are obligated in the requirement of tithing. The Mishnah on yesterday’s daf (=page) teaches that if someone purchased an animal or received it as a present, there is no obligation to tithe that animal, as only animals that are born as someone’s property must be tithed.
Continuing that theme, the Mishnah on today’s daf teaches that partners are free of the obligation to tithe their animals; similarly brothers who are partners in their father’s inheritance, i.e., it has not yet been divided up between them, are not obligated to tithe them. The Mishnah connects this rule with another: those who are obligated to pay kolbon are free from the obligation to tithe their animals.
The term kolbon is taken from the Greek, meaning a small coin used for payment of the surcharge when change was made with a money-changer. According to the Torah, every Jewish person was obligated to contribute a half-shekel (mahatzit ha-shekel) to the Temple to help pay for the communal sacrifices. The Sages established as a rule that everyone was obligated to add an additional coin – a kolbon – as a surcharge for the change that was to be given when exchanging a shekel for a half-shekel. This was set as a rule, so even if two people came forward and paid their half-shekels together, so that there was no need to offer change, nevertheless, the kolbon had to be paid.
The Mishnayot in Masechet Shekalim (1:6-7) teach that there is an exception to this rule. If someone paid the mahatzit ha-shekel on behalf of another, there was no requirement to pay the kolbon. Therefore, if a father pays for his son, he does not have to pay the kolbon. Our Mishnah teaches that when two brothers pay the mahatzit ha-shekel from the inheritance before it is divided up between them we view it as though the father was paying for them and there is no obligation to pay the kolbon.