Calm down everyone !!! There seems to be a bit of 'closing ranks' and being fairly hostile on the subject. It is a straight forward question, and the answer is as per replies 2 & 3 above.
Yes, you can land pretty much anywhere, subject to land owners permission, but you are liable for any damage done. Any site can be used as a one-off landing site and when I say one off, I mean 'occasional'. If you want to use it as a regular helipad, there are some hurdles to get over.
In repect to your particular issue, I have found livestock to be rarely bothered by the noise of helicopters. Low level flying in the army has its obvious issues in that horses (and more vitally, riders on horseback) don't always hear you coming until the sudden onset of noise flying over head. In normal civil flying, landing at a remote site, you will orbit once or make a steady approach looking out for any obstacles and that steady build up of noise reduces any alarm from animals on the ground.