He added: "All dogs, whatever their usual temperament, are capable of chasing livestock.  This behaviour can have severe or even fatal consequences for these animals as well as both an emotional and financial impact on the farmer. 

"We're urging anyone who may have information about this incident, or who saw a dog matching this description and being walked by a woman in the area, to contact us. 

"We're still working to establish the full circumstances surrounding this and if the owner sees this appeal I'd ask them to get in touch with us as soon as possible to help with our ongoing inquiries."