An electric fence displays a warning sign about voltage and amperage of the fence. How would amperage and voltage affect the power of the fence?

Yes it is true that electrical fences displays a warning about voltage and amperage of the fence. It has to be first understood that power is directly proportional to voltage as well as current. So higher the voltage or higher the current flowing through the fenses, higher will be the power. So any person touching the fence should always be aware of the voltage and current flowing through the fence, otherwise it can be very deadly. Sometimes it can be seen that a high voltage is being passed through the fence and the current passed is comparitively low. This will not decrease the total power flowing through the fence.