If you want to record social interactions of individuals you will need to be there personally, with an image intensifier. If you are only interested in herd activity some kind of time-lapse photography would be OK. If you are interested in behaviour of individuals and don't need to know about their social interactions, pedometers for dairy cattle are freely available. Recording bout lengths of behaviour can be very rewarding - I did this (many years ago!) Hall, SJG (1989) Animal Behaviour 38, 215.

Thanks Stephen I would consider those suggestions.

Make sure that you sample at regular intervals throughout the day and night. You do not need to sample continuously, but you should have observation sessions of at least 1 hour about every 4 to 6 hours. If you are interested in interactions between individual animals, you will need some identification system that will be useful during the dark.

Thanks Jack for the suggestion

The biotelemetry technologies using GPS, UHF proximity loggers and wireless sensor networks (WSN) are advancing and have the potential to document the behaviour of cattle in rangelands. The technology is hands-off and noninvasive but the initial issue is to accurately match the telemetry data with the behaviour and this can only be achieved through observation.