Animals don't rank as high in Mexico as they do in the US. In fact it is fairly recent for dogs to really be accepted as pets. We had a hard time trying to find someone to watch Britches (our yorkie) when we were going to Mexico City. We checked at the best vet in town. They had a kennel, but it wasn't a place we were comfortable leaving her. Most people seem to just leave their animals at home and get someone to check on them every once in awhile.
When I was reading about coming to Mexico, several people mentioned that people from the US are usually shocked at how Mexicans treat animals because animals are treated so well in the US. They also mentioned that most Mexicans are shocked at how poorly people from the US treat their children!