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85% of male calves used for beef are castrated. The most common method used is applying a tight rubber ring around the scrotum to cut off blood supply and sever it from the body. Calves or bulls are castrated to make their flesh tenderer and to simplify management.
Castration is painful procedure for calves. A study from New Mexico State University stated
Pain is inherently a part of castration and cannot be avoided. The pain of castration occurs first as acute, short-term pain associated with the actual castration procedure. Chronic pain is the longer-lasting pain that occurs in the days following castration until the injury is healed
For rubber band castration no anesthesia is required if the animal is under a week old, for any other method (such as surgical removal) no anesthesia is required if the animal is under two months old.