“There seems to be several times that bull calves are castrated: at birth, at branding time, prior to moving the calf and dam to spring/summer pasture, at weaning, and, sometimes in the seedstock business, after weaning,” says Rick Rasby, beef specialist at the University of Nebraska. There is some debate over the “best” time to castrate, but whatever time you choose, make sure it is done to avoid infection and keep stress as minimal as possible.
Research has shown the least stressful time for castration is at birth. “Usually, the procedure is using a rubber band that fits tightly around the scrotum and next to the body. The blood supply to the scrotum and the two testicles in the scrotum is stopped and necrosis occurs and, after about a month, the testicles and scrotum fall off.” But you have to make sure both testicles have descended and are in the scrotum before the band is put on.
As the animal gets older, there is more stress, and you need to use extra caution since the blood supply and nerve development to the testicles increases as the animal matures. If you choose to use the knife method for castration, make sure you have adequate facilities to contain the animal, and make sure the calf has access to a clean area and that the flies are controlled. You can contact your veterinarian for tips on surgical castration.