NFU Cymru has called for dog owners to keep their pets on a lead around livestock after sheep were killed and injured on a union official's farm.
Wyn Evans, who farms near Aberystwyth, has lost 7 ewes and a further five were injured after the attack involving two lurcher-type dogs on New Year’s Eve.
The incident is currently being investigated by Dyfed-Powys Police’s Ceredigion Rural Crime Team.
NFU Cymru is urging dog owners to enjoy the countryside responsibly and to keep their pets on a lead to avoid sheep worrying or attacks on livestock.
While the vast majority of owners believe that their pet is docile and would not harm other animals, dogs can cause distress, injury and death to sheep.
Livestock Board Chairman Wyn Evans said: “Sheep farming is more than a livelihood for our family. We have responsibility for the welfare of every animal we have on the farm.
"To see our pregnant ewes maimed and killed in this manner has been a very upsetting experience for us. It is something no farmer should have to go through.
"Please act responsibly and keep your dog on a lead when livestock are nearby.”
NFU Cymru's website has advice to support farmers in the event of a dog attacking livestock, as well as resources to help encourage the public to walk their dogs responsibly on farmland.
Mr Evans added: “It is crucial that farmers report incidents of this nature to give our police forces a true picture of the scale of the problem.
“It is similarly important that our rural police teams have the resources to respond to crimes of this nature swiftly and effectively."
The news follows a livestock worrying incident on Christmas Eve, in which an out-of-control dog killed 30 sheep on a farm in Cheshire.
And in a separate incident in December, a loose dog massacred 46 sheep in Suffolk.