Rottweiler dogs are known for being loyal and protective of their owners. Purebred Rottweiler's have very distinct coat colouring and features that make them easy to identify. The coat of the Rottweiler is always straight and coarse, and is black with brown or rust coloured spots on the muzzle, and on all four legs including the inner hind legs. Some Rottweiler's have white spots or patches of fur on their chest. According to the American Kennel Club, this is an undesirable trait for Rottweiler's that you plan to show or breed.
Purebred Rottweilers that have white patches on their chest are thought to be genetically defective. White markings are an indication of poor bloodline breeding according to show standards. In spite of the white markings, the dog will likely behave appropriately. Don't let white markings on the chest alone hold you back from choosing a Rottweiler as a pet. Interact with the Rottweiler to make sure that it doesn't have other undesirable traits that can be linked to poor breeding, such as nervousness.
Some Rottweilers show a few white hairs but lack the white patch on the chest. This doesn't necessarily mean that there is a genetic defect, it could merely mean that the individual Rottweiler has unique characteristics. Your Rottweiler may be a purebred with a few white hairs or a white patch; some people mistake them as being crossed with another breed of dog in spite of the fact that minimal white markings on a Rottweiler can be common.
Be prepared to face scrutiny if you are breeding Rottweilers that have the white patch of fur on the chest. Many Rottweiler enthusiasts find this to be the fault of the breeder and will decline to take a dog with the white patch. Focus on selling Rottweiler's with the white patch to people who are not planning on showing the dog or breeding the dog themselves. The American Kennel Club recommends spaying or neutering any purebred Rottweiler that has any white markings.
A Rottweiler's undercoat shouldn't be visible to the eye without grooming or close inspection; with a well-bred Rottweiler, the coat should lay flat. The undercoat usually contains brown and even lighter tones such as white hairs. Glance at your dog's undercoat during grooming to see if your dog contains this trait. If you plan on showing your dog, stay away from Rottweiler's that not only have white markings but that also have wavy or curly fur.