Vets are asking dog owners to keep their animals on leads when walking near sheep as the lambing season gets under way.
Ewes are particularly vulnerable at this time of year, as they prepare to give birth, and sheep worrying can have tragic consequences.
It is good practice for owners to keep dogs on leads at all times when walking near livestock but it is particularly important during spring.
Vets have seen a rise in the numbers of attacks, the results of which may often lead to lambs being lost and sheep being killed and injured.
British Veterinary Association president and vet Robin Hargreaves said: “Even dogs which are usually calm and good-natured can become very excitable and difficult to control when faced with livestock.
“This can lead to chasing, attacks and fatalities for sheep and other animals.
“Over the coming months ewes in the field are likely to be heavily pregnant or to have recently given birth. Chasing and worrying can have severe consequences at this time, leading to serious injuries, early labour and fatalities.
“Later in the season the arrival of lambs brings fresh temptation as their energy and activity can be irresistible to dogs.
“We ask that owners in rural areas keep their dogs on leads when walking near livestock. They should also consider taking alternative routes during the lambing season to avoid causing distress.”
Fiona Lovatt, president of the Sheep Veterinary Society, has worked with sheep farmers in County Durham and across the country.
She said: “The results of these attacks are very distressing for the sheep, the farmer and for the vet.
“I’ve treated sheep which have been practically shredded by dogs and you often have no choice but to put them down.
“At this time of year a dog attack can have drastic effects even for the ewes which are not injured, as the stress may cause them to abort.
“I think most owners are well-meaning but if your dog is off the lead you may not even be aware of the chasing or attack. It’s important to know where your dog is at all times as they can cause a lot of damage in a short time.”
Two sheep were recently savaged by dogs in the Lake District.
Lake District National Park ranger Steve Tatlock said breeding ewes in fields near Bowness-on-Windermere had been savaged, leaving their ears badly torn and faces gashed.
He added: “Farmers have reported some sickening cases over the years and ultimately they have a defence for shooting dogs in the protection of their animals.
“This is obviously a last resort, but sometimes they have no other choice.”
Mr Tatlock said out-of-control dogs were also to blame for attacks on ground-nesting birds and their offspring.
“Species such as curlew, lapwing, snipe and grouse have nests disturbed by dogs and their chicks scattered. And once away from the nest, their chances of survival plummet. We’ve seen a worrying decline in numbers.”
By law, canines must be controlled so that they do not scare or disturb livestock or wildlife. On open access land they have to be kept on short leads from March 1 to July 31 – and all year round near sheep.
Close supervision is also required on public rights of way.