Dog attacks on farm animals are thought to have cost over £115,000 last year, according to an insurance survey.
Many dog owners have chosen to walk their pets in rural areas during the pandemic and more than half (64%) admitted in a survey commissioned by rural insurer NFU Mutual they let their dogs roam free, even though half said they don't always come back when called.
There are fears lockdown into spring will see a further increase in dog walkers unfamiliar with the countryside code and how their pet will act around animals.
In 2020, the cost of dog attacks on livestock UK-wide reached an estimated £1.3m - an overall increase of over 10%.
"With more people walking in the countryside as COVID restrictions continue and an increase in dog ownership, we have seen horrific attacks resulting in large numbers of sheep being killed and a trail of horrific injuries,” said Martin Malone, Northern Ireland Manager at NFU Mutual.
Such attacks cause unbearable suffering to animals and cause farmers and their families huge anxiety, he added.
"We want people to enjoy the countryside as it’s so important for people’s wellbeing. It’s vital that dog owners act responsibly and keep dogs on a lead whenever there is a possibility livestock are nearby."
However, only slightly less than half of dog owners surveyed accepted that their pet could cause the injury or death of a farm animal.
Sheep farmers are now entering the peak lambing period and both pregnant ewes and new born lambs are vulnerable to attack.
All dog breeds are capable of chasing livestock, said Mr Malone. "Even if a dog doesn’t make physical contact, the distress and exhaustion of the chase can cause sheep to die or miscarry their lambs."
Ulster Farmers Union (UFU) deputy president David Brown said it's "extremely frustrating" as a farmer to see dogs let loose by their owners, especially near livestock.
"Livestock worrying has always been an ongoing concern for our members, but it has heightened even more due to the increase in dog ownership and with more people venturing to the countryside to exercise," he said.
"With spring lambing approaching ewes are heavily pregnant and any chase by dogs no matter how small can result in a ewe aborting her unborn lambs."
"The essential approach is for dog owners to make sure their dog is on a lead at all times and that they have complete control," he said.
"This is the only way to ensure no harm comes to livestock and that walkers and their pets can enjoy the countryside peacefully."
In Northern Ireland, local Council dog wardens investigate and respond to livestock attacks as per the Dogs (Northern Ireland) Order 1983.
NFU Mutual is issuing the following advice: