1 / 4   Jon Gelleran, a veterinarian in Denver, Colorado, US, has set up the 'The Street Dog Coalition' a mobile street veterinary clinic, to give free veterinary services to pets of homeless people. /VCG Photo

2 / 4   The coalition is staffed by volunteer veterinarians from all over the US. Veterinarians gave the pets free medical care and other services at the center, including microchips and vaccines. /VCG Photo

3 / 4   The animals were also tested for, and if the result found negative, they were given heartworm medication. The veterinarians also gave general examinations for all the animals. /VCG Photo

4 / 4   More than 100 dogs and cats received free medical treatment thanks to volunteer veterinarians at 'The Street Dog Coalition.' /VCG Photo