Sheep rustling anger in Swansea, Amman and Lliw Valleys
Farmers in the Swansea area are calling for more police action over sheep rustling they say has cost them about £30,000 over the past 18 months.
The West Glamorgan Commoners' Association says seven of its members have lost 350 sheep in the Swansea, Amman and Lliw Valleys in that period.
A farm insurer says livestock thefts cost Welsh farmers £700,000 in 2011 and it expects a similar figure for 2012.
South Wales Police said they were planning to take targeted action.
Thefts are known to take place in the late summer or early autumn, and the farmers say it has gone on for too long.
They say they have seen vehicles and trailers being driven around late at night and they fear animals could also have been taken since November.
Local farmer Bernard Fox said farmers were starting to question whether it was viable to continue to turn out sheep into the countryside as they were not assured they would be there when it was time to round them up.
"Somebody is making a lot of money," he said.
"They have to have knowledge and experience of handling sheep. No novice could do this.
"At the end of the day it is up to the police to apprehend these criminals and give us all a good night's sleep."
NFU Mutual, which provides insurance for a large number of Welsh farms, said it was waiting for final claims figures for 2012, but there had been a four-fold rise in animal thefts in Wales in 2011, coinciding with a rise in sheep prices.
It estimates the cost of animal thefts to have been £700,000 in 2011 and about the same in 2012.
Sgt Andy Abraham from Pontardawe Police Station said South Wales Police planned to work closely with the commoners association, the National Farmers' Union (NFU) and the neighbouring Dyfed-Powys force to tackle the problem.
"This is an issue that we take very seriously and that is why this spring we will be launching an initiative which is aimed at tacking the widespread theft of sheep," he said.
"There are difficulties in investigating these crimes due to the terrain and the remote areas where the sheep are being stolen."
Sheep farmer Bob Woolston said: "The problem is getting worse. I've have lost sheep over the last three years that I know of. I've lost 20-odd this year, last year 60 lambs."
He said gates and locks are broken before the animals are taken, usually after dark.
"There have been people there who have cut the fences since November," he said.
Police asked people with information to call police on 101 or Crimestoppers on 0800 555 111.