POLICE in west Cornwall say they are investigating a "worrying increase" in offences of criminal damage to isolated local hill farms.
The attacks started in 2008 and over recent weeks police said they have increased dramatically.
Incidents usually involve dismantling and removing gates and fences, cutting or creating holes in the water troughs, and sawing through metal panels in feeders, according to police.
Devon and Cornwall Police said that, as a result of these crimes, cattle and ponies are either left without a water supply, which is cruel to the animals, or they are escaping onto the roads which is extremely dangerous to other road users.
The attacks are also costly and have an impact on traditional and often historic gates and fences.
Grazing on the moorland has been carried out for many years and some of the fences and gates that have been damaged have been in place for 15 to 20 years.
The victims are farmers who graze cattle on moorland owned by the National Trust and other private landlords, said Devon and Cornwall Police. They include Bosigran, Lanyon, Trevean and Bosporthennis farm.
The first attacks in 2008 coincide with the start of the Higher Level Stewardship scheme run by Natural England.
The HLS grant funds farmers to maintain moorland through a variety of options, from cutting bracken to grazing Highland cattle on particular sites - some of which are ancient monuments.
Sergeant Cara Trott, neighbourhood team leader for the area, said: "Police are investigating these incidents and anyone caught will be prosecuted for criminal damage.
"Whatever the motive, these incidents are criminal and are also extremely dangerous. Cattle and ponies getting onto the winding roads where people are not expecting them could result in someone getting killed.
"One of these farms has been attacked at least fifteen times since September alone.
"I would urge anyone carrying out these offences to stop before someone is seriously injured. We will do everything we can to find out who is responsible so that these farming families can live without the fear of continually being victimised".
Anyone who has any information or has witnessed any of these incidents should call Devon and Cornwall Police on 101 or Crimestoppers on 0800 555111 quoting crime reference AP/13/56
