Farming bodies have called on dog owners to control their animals, after the latest attack wiped out generations of a pedigree sheep flock.
Tim Kelleher, from Kilmichael, near Macroom, Co Cork, said he was sickened after witnessing the horrific damage wreaked on his flock of pedigree Zwartbles sheep.
"I lost three generations in the attack," he said, including a €1,000 ram destined for an All-Ireland competition.
Mr Kelleher, a part-time farmer who works in the post office in Macroom, said he discovered the devastating damage to his flock of 30 ewes and lambs at 11pm on Monday, last week.
He said seven were dead following the dog attack, one died later, and more were left badly injured, all at a minimum cost of €8,000.
"I saw the wool first and then I shone the lights in the field. A ram I gave STG£700 (€980) for was just lying out flat. It was horrific," he said, adding there was no sign of a dog by the time they arrived. "My partner is pregnant with her third child and she was vomiting she was so upset.
"I was so upset I couldn't shoot the sheep - I had to ring a neighbour."
Mr Kelleher, who appealed to dog owners to keep their pets under control, said he will feel the cost for years.
"This is not just this year but next year. I'll be down 20 lambs. It is the rippling effect. It is becoming way too common a thing. One of the ewes died in my arms - I lost a grandmother, daughter and her daughter. I'll have to start all over again," he said.
"One of the ewes got second prize in a Cork show on Sunday and I'd to shoot her dead the following day," he said, of one of the black-coloured breed which have a distinctive white stripe on their faces.
The Irish Cattle and Sheep Farmers' Association sheep chairman John Brooks has urged dog-owners to be responsible.
"All dogs, from cherished family pets to prized working dogs, can potentially cause serious distress," he said.