Does the quarter that the grandfather vowed for the sick buffalo—if it recovers—also apply to its offspring, or only to the buffalo itself?

The grandfather vowed a quarter of the heifer to the poor if it recovered from its illness. Upon its recovery, a quarter of it must be given to them. And a quarter of what the heifer gives birth to is also given to the poor, because the offspring of a vowed animal follows the vowed animal itself.