Have you contacted vet offices and low cost neuter/spay clinics? Since he is intact and someone may be keeping him, the finder may go and have him neutered.
Jennifer
Lost on 8/4 at Boulder & Lake Mead. He is tan & white and weighs 30 lbs. There is no picture attached.
If there is anyone in the area that could help, please contact the owner.
Here is the ad:
http://lasvegas.craigslist.org/pet/3185722272.html
Jennifer