grinders is very apparent. At ten or eleven years, used surfaces of the teeth begin to bear a square mark surrounded by a white line, and this is pronounced on all the teeth by the twelfth year; between the twelfth and the fourteenth year this mark takes a round form. It is a requirement in some locations that prime cattle have a dentition indication mark on them prior to auction. This is normally done by the vendor, or the stock agent. Fat cattle auctions in New South Wales, Australia identify the amount of teeth that prime animals have in the form of sprayed marks along the back. Thus two tooth cattle are marked on the wither, four tooth on the middle of the back and six tooth on their high bone (near tail). Milk and eight tooth cattle are not marked. Horn method The rings on the horns are less useful as guides. At ten or twelve months the first ring appears; at twenty months to two years the second; at thirty to thirty-two months the third ring, at forty to forty-six months the fourth ring, at fifty four to sixty months the fifth ring, and so on. But, at the fifth year, the three first rings are indistinguishable, and at the eighth year all the rings. Tail brush method The brush of the tail is only useful as a guide when assessing small, stunted or young cattle. A brush that is about fetlock length or longer is an indication that the beast is twelve months old or older. This method cannot be used on cattle which have been bang-tailed. Bang tailing is the act of cutting the long hairs at the tip of the tail short to act as a simple identifier of animals and is commonly used after a procedure has been performed on an individual animal that belongs to a large mob e.g. the mob is run through a race and each animal is vaccinated – immediately after being vaccinated the animal is bang-tailed so they are identified as vaccinated and will not be given a second dose of vaccine. This is useful when large numbers of animals are being processed by a group of individuals. Other methods Cattle age in a carcass is determined checking the physiological skeletal maturity (ossification) (red) of the tips or "buttons" of the thoracic vertebrae. The size and shape of the