Nev. Rev. Stat. § 574.650
1. Except as otherwise provided in subsection 2, if a new owner presents to the releasing agency a letter signed by a veterinarian which includes:
(b) The veterinarian’s medical reason for that determination,
the releasing agency may postpone for 30 days the date by which the pet must be sterilized. An additional 30-day postponement may be granted if the new owner presents a letter from a veterinarian stating the medical reason for the postponement. There is no limit on the number of postponements that may be granted pursuant to this subsection.
(Added to NRS by 1997, 2556)