The most recent was at the weekend, when three ewes died and one lamb went missing, Phil Bradley said.
"I went out on Sunday morning to shift them, to find all this carnage down the back paddock. It's not a nice sight to see your sheep laying around like that."
One ewe was dead and one had to be put down later that day. A third one he thought "might pull through" died on Sunday night, he said.
"I'm pretty sure it's two dogs involved, one at the front of the animals and one at the back, similar to what happened last time."
In mid-August, two of his in-lamb ewes were killed outright during a dog attack on his 3.2ha property near Clyde, and three other ewes were so badly injured they had to put down.
"So, now I have one remaining ewe from a flock of nine.
"She had triplets and it's one of her triplets that went missing at the weekend, so I guess the dogs got it, too."
A couple of dogs have been seen near the property on several occasions, so Mr Bradley believes the same two dogs are responsible for both attacks.
"I don't know what to do now.
"I originally got the sheep to keep the place tidy and keep the grass down, so it wasn't a fire hazard. Am I supposed to get cattle instead?
"I don't want to put up a deer fence to keep the dogs out."
"I like dogs ... but this has got to stop," he said.