Two Western American Indian tribes are working with veterinarians to study the use of a contraceptive vaccine that's been used in wildlife to keep populations under control. Under the program, veterinarians will capture 300 wild female dogs and administer the government vaccine GonaCon. The animals will also be microchipped, collared and tattooed before being released. They'll be recaptured after a year to assess their response to the vaccine. The research is a collaboration between the USDA National Wildlife Research Center and Oklahoma-based Spay First.