Texas longhorns have the longest horns of any cattle. The first signs of the horns can be seen at the age of just three weeks. The horns grow sideways out of the head and twist slightly at the tips. By around the time a bull turns one, its horns will already have grown to around half their adult length. A Texas longhorn bull is fully grown at the age of four, when it weighs between 680 and 1,000 kg.