When the gemarrah initially explains abaye (1/4 nezek from the cow and 1/8 from the calf, the gemarrah explains that the calf and cow are owned by two separate people. Even if there is one owner, if the calf was born prior to the damage, he had nothing to go with the damage. If the cows value is less than chatzi nezek, how could the owner be expected to make of the full chatzi nezek from the value of the calf, if it's participation in the nezk is questionable?
Bruce Mosenkis, Beit Shemesh
Shalom Bruce,
I hope understood your question correctly. You are making an assumption that the cow is worth less than half the damage, and then you are asking, according to that, what difference does it make whether the calf was born before or after the damage. If you remove this assumption, and assume that the violation is worth more than half the damage, everything works out.
When there is a calf "inside" the cow, the perception is that the calf also shares in the damage. This is significant only when the calf belongs to another person, then we can talk about dividing the damage. When we have a doubt about whether the calf was born before or after the damage, then according to Sumchus, the owner of the calf will pay half.
Best Regards,
Aharon Steiner