Depending on where you live there are many ways to supply water to your cattle.
Dugouts, Slough, Ponds and other natural sources of water
There are several methods of handling this. You can let the cattle drink from the water source naturally. However, this will cause erosion and change the shape of the pond. This can be beneficial at times especially for a dugout where minor erosion around the dugout will speed the process of naturalization and increase holding capacity. However, this is often more harmful than beneficial and it is recommended by many sources that if you can afford it you install a solar or wind powered pump and fence off your water source. With this set up you can water your herd from a trough and in northern climates can water them from this water source all year round (as long as the pump is below the maximum ice depth).
Watering them in from a well or other man made source
For this you will need a trough and a hydrant or other form of a tap connected to a well. If you are lucky and have a deep well or a separate well for your cattle then you can constantly water your herd without running out. However, if you are sharing a shallow well with your herd and household water supply then you might run out of water if you need to supply too much. If this is the case you may need to limit the size of your herd even more than local regulations may dictate.