The Rottweiler

The Rottweiler is a medium to large size breed of domestic dog. The dogs were known as "Rottweil butchers' dogs" (German: Rottweiler Metzgerhund) because they were used to herd livestock and pull carts laden with butchered meat and other products to market. Some records[which?] indicate that earlier Rottweilers may have also been used for hunting, although the modern Rottweiler has a relatively low hunting instinct.
The Rottweiler was employed in its traditional roles until the mid-19th century when railways replaced droving for getting livestock to market. While still used in herding, Rottweilers are now also used as search and rescue dogs, as guide dogs for the blind, as guard dogs or police dogs, and in other roles.

Temperament 
not to be neglected. It is for this reason that breed experts recommend that formal training and extensive socialisation are essential for all Rottweilers. According to the AKC, Rottweilers love their owners and may behave in a clownish manner toward family and friends, but they are also protective of their territory and do not welcome strangers until properly introduced. Obedience training and socialisation are musts.
A 1997 report by the CDC on dog-bite-related fatalities in the U.S. reported that Rottweilers were the second most likely dog to be involved in fatal dog attacks on humans (29 deaths over 20 years), after Pit Bulls (60 deaths over 20 years). In 2011, of the 33 recorded dog attack fatalities in the U.S., four were by Rottweilers.[citation needed]
Breed-specific bite rates are not known, and less responsible owners being drawn to certain breeds may be a factor.[14] Dogs bite approximately 4.7 million people in the U.S. each year, with fewer than 30 dog-bite-related human fatalities from a total dog population estimated by the American Pet Products Association at 77.5 million dogs. A 2008 study surveying breed club members found that while Rottweilers were average in aggressiveness (bites or bite attempts) towards owners and other dogs, it indicated they tend to be more aggressive than average towards strangers. This aggression appears correlated with watchdog and territorial instincts.
Rottweilers have been banned in some municipalities, and they are sometimes targeted as dangerous dogs by legislation, such as in Poland, Portugal and the Republic of Ireland.

Working Style
generally show a loose-eye and have a great amount of force while working well off the stock. They make much use of their ability to intimidate.
The Rottweiler often carries the head on an even plane with the back or carries the head up but with the neck and shoulders lowered. Some females lower the entire front end slightly when using their eyes. Males also do this when working far off the stock in an open field. This is rarely seen in males when working in confined spaces such as stock yards.
The Rottweiler has a reasonably good natural balance, force-barks when necessary, and when working cattle uses a very intimidating charge. There is a natural change in forcefulness when herding sheep. When working cattle it may use its body and shoulders and for this reason should be used on horned stock with caution.
The Rottweiler, when working cattle, searches out the dominant animal and challenges it. Upon proving its control over that animal it settles back and tends to its work.
Some growers have found that Rottweilers are especially suited to move stubborn stock that simply ignore Border Collies, Kelpies, and others. Rottweilers use their bodies to physically force the stubborn animal to do its bidding if necessary.
When working with sheep the Rottweiler shows a gathering/fetching style and reams directions easily. It drives sheep with ease.
In some cases Rottweilers have begun herding cattle without any experience at all.
If worked on the same stock for any length of time the Rottweiler tends to develop a bond with the stock and will become quite affectionate with them as long as they do as it directs.
( Source : wikipedia )