Irish and European pasture based systems of farming rely upon precise grass allocation which requires a high labour input for its successful implementation. The " Virtual fence " is a method of cow containment with the use of aversive stimuli through the medium of an on-cow collar. As the cow approaches the GPS boundary she are issued a warning stimulus, if the cow fails to take notice of the warning she will receive a low level electric stimulus. This technology has the potential to reduce labour associated with grass allocation and cow containment in a paddock. However, the feasibility of virtual fence technology will rely on the ability to successfully train and contain cows within a paddock using virtual fence collars. The aim of this study was to assess the functionality of virtual fence technology for practical implementation on farm. Cow trials were conducted to evaluate: different training methods, GPS (global positioning system) accuracy, effect of different warning stimului (audio and tactile), and battery life and hardware design. The results of this study identified conceptually important parameters intrinsic to the functionality of virtual fence technology within a dairy system integrated with grazing. The future applications for the " Virtual fence " may be considered as feeding to yield on an individual cow basis, fetching cows that have an extended milking interval on an automatic milking system as well as fetching cows in the conventional system.