A US farm has started equipping its goats with GPS collars so they can be fenced in electronically, with no physical fence necessary.

Just nine hours after installing GPS in machines that slowly water corn and soybeans on his family's farm, Hunnicutt's brother saw on his iPad tracking app that two of them were about to collide.

The app uses the phone’s GPS to track and map as equipment goes up and down the fields planting or spreading fertilizer. Everything on the phone is synced with their web account.

A US farm has started equipping its goats with GPS collars so they can be fenced in electronically, with no physical fence necessary.