The British Veterinary Association is stressing that ewes are particularly vulnerable at this time of year.
And they have made the tragic consequences of sheep worrying clear.
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.
Precise figures for the numbers of sheep and other livestock injured by dogs are not collated. But statistics obtained by Farmer’s Guardian under the Freedom of Information Act showed reported dog attacks on livestock increased from 691 in 2011to 739 in 2012.
The real figures may be much higher as many farmers do not report attacks.
BVA President and vet Robin Hargreaves said: “It is good practice for owners to keep dogs on leads at all times when walking near livestock but it is particularly important during the spring.
'A lot of damage in a short time'
Fiona Lovatt, President of the Sheep Veterinary Society:
“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 that 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.”
“Even dogs who are usually calm and good natured can become very excitable and difficult to control when faced with livestock. Tragically 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.”