Water pipe extension to livestock corrals
A lot depends upon whether you live where it can freeze. If you do then you want to bury the pipe from the house to the stock tank in the ground at a depth sufficient to prevent freezing. Then you want to use a frost-free farm or yard hydrant type valve to join with the buried water line and bring the water service up to the working level above the ground. The hydrant has an actuator lever at the top the works a rod inside the pipe all the way down to the actual water shut off point under the ground. When the rod is pushed down so that the water flow is off the hydrant is designed to drain the riser pipe through weep holes at the bottom. This prevents freezing of the riser pipe above ground.

Some hydrants will require the addition of a back flow preventer if you intend to leave a hose attached while the hydrant is off. This so that the drain feature will work correctly by letting air into riser pipe. 

The auto drain feature is one reason it is necessary to lay in a good amount of pea gravel or crushed rock around the bottom of the hydrant so that it is easy for the water from the drain feature to flow away from the pipe and down into the surrounding soil.

Here is a picture of a typical hydrant: