Pet owners are being warned to be vigilant after a rise in dognappings.
A total of 38 dogs were stolen in Essex last year, with gundogs and labradors the most targeted breeds.
The Country Land and Business Association believess the figure will rise because animals can be sold quickly and are not easy to trace.
Nicola Currie, regional director, said: “The temptation on a hot day is to let your dog go unattended into your garden, or out on your land, to find some cool shade.
“It’s also easy to let it run free and go out of sight while you are on walks.
“Unfortunately, this offers thieves a golden opportunity to take your animal.
“Many dogs are targeted by thieves because they can make money selling them on, often for breeding or for fighting.
“By leaving a valuable and much-loved animal in your garden in sight of a road or a public right of way gives thieves a chance to monitor your movements and security arrangements with a view to possibly stealing it to order.”
The website doglost.co.uk, which helps reunite owners with lost animals, has had 26 listings of lost dogs from the Colchester postcode area since the beginning of last year.
Meanwhile, in Southend and the surrounding areas 23 dogs have been reported as going missing.
The website believes gundog theft has increased as former metal thieves have turned their attention to stealing working dogs after metal laws were tightened two years ago.