Cruelty to animals is UNACCEPTABLE!!!
Most animals trust us humans, and as much as I hate to say it, there are many who are not trustworthy.
What can YOU do if you see an animal being mistreated? Just keep a watchful eye! It may be as simple as noticing a dog without shade, water, or shelter from the elements to as serious as signs of malnutrition or open wounds.
Before contacting the authorities, first observe the problem and document EVERYTHING. The time, location, people involved, how long this has been happening and what you've witnessed. Of course, in extreme cases, you may have to call someone sooner. Photos or video can help prosecute animal offenders, or at least get the animal removed from the situation. Authorities will accept annonymous reports.
Speak up for those who can't speak for themselves. It's what GOOD humans do!
Here's a sad case with a good ending http://www.huffingtonpost.com/2012/09/18/patrick-the-miracle-dog-_n_1894325.html#slide=1538255