Australian Stumpy Tail Cattle Dogs are not Australian Cattle Dogs with docked tails, though they shares history similar to that of the Australian Cattle Dog. They are a breed in their own right, the principle difference between them being that unlike the Australian Cattle Dog, the Stumpy Tail has no Kelpie blood. Most sources credit the Smithfield Cur (a dog that appears in the ancestries of both breeds) for carrying the gene for taillessness. Selective breeding of bobtail to bobtail made this characteristic fixed in the Australian Stumpy Tail Cattle Dog. “Stumpies” are prized in Australia for their working ability, and very highly sought after. In fact, there are those who believe the breed has no peer when it comes to working cattle. For more comprehensive information on the breed, read the piece that appeared in Canine Chronicle here.
The Australian Stumpy Tail Cattle Dog was provisionally recognized by the FCI in 2005.
Image of an Australian Stumpy Tail Cattle Dog By Wendy Hodges http://www.flickr.com/photos/ittypuddies/6242167025/, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=16981432