Researchers have shone fresh light on a painful condition that causes dogs' tails to lose their wag.

A team at the University of Edinburgh has carried out the first large-scale investigation of limber tail, an illness that causes the tail to become limp and painful.

The condition mostly affects larger working dog breeds such as labrador retrievers and the study compared 38 cases of dogs with the condition with 86 which had no symptoms.

It found that dogs with limber tail were more likely to live in northern areas, supporting anecdotal reports the condition is associated with exposure to cold.

Labradors that had suffered the illness were more likely to be related to each other than unaffected dogs, possibly indicating an underlying genetic risk.

The condition is sometimes known as "swimmers' tail" and some, but not all, of the affected dogs had been swimming before the onset of symptoms.

Dr Carys Pugh, who led the study at the university's Roslin Institute and Royal (Dick) School of Veterinary Studies, said: "We were surprised by how many owners were reporting limber tail to us but it meant we had the chance to do a detailed investigation.

"We have been able to add evidence to a lot of internet speculation about risk factors and the new findings relating to geographical region and family links give us avenues to pursue in understanding and avoiding the condition."

The study was conducted as part of the Dogslife project, which follows the health and wellbeing of more than 6,000 labradors across the UK.