have to weigh in on this. We band at birth. No open wound, no problem with flies. If you have a problem getting two, we leave them until branding and then if you cannot get two in the band, you knife cut them. That might be one calf a year. On a different ranch we used Chemcast and ended up coming back and knife cutting about 200 head, with the testicles adhered to the scrotum, one of the worst jobs ever. We also have had an experience with leaving them until weaning. Beartooth Beef wanted all natural, non castrated bulls for their meat program. We went along with it only to have the thing fold in the second year. So we had 200 head of bulls to castrate at weaning. Used the EZ castrater, worked my butt off for a whole day doing them. Sure they weighed more than steers but then the next two months in the feedlot they gained a pound a day, rather than the 3 that steers gained. Net gain zero. band them at birth and the animal rights people cannot get on you for cutting an animal without anesthetic and traumatizing animals in our care. I actually got this question put to me at a beef symposium and I will stick to my answer then, band at birth. There is research that has proven that banding at birth is the way to go, I do not remember where it was done but they compared weaning weights of banded at birth to knife cut to banded at branding. band at birth