The rule i go by in cutting calve's came from my uncle about forty year's ago , make sure they have good drainage out of the sack like one of the guy's said. Also use disinfectant for knife an we throw some on the bag before an after, there is a disinfectant that help's with the healing, an we use those small rubber veterinary glove to reduce infection an keep hand's clean. When you go to pull the cord,an this is more for the older calve's three mo, to one year do one at a time an pull steady an try to get it to snap way back in the calf , I wrap the cord around my finger's to help pull steady , some times if I Donny have glove's it will get tight enough to cut my hand. One of the vet's told me that as long as that calf is not a year old it has enough elasticity to snap that closed. DO NOT use a knife to CUT OR HELP IT BREAK.If it would happen to break early an you can see any hanging out of bag or up in it try to pull more out. This will happen some time's. Also when you firs grab cord you might need to push back some of the flesh or fat to get down to the cord. I've used this for about forty year's or more an I think Might have lost one calf. We cut about fifty calve's a year this way an they are 6 month's an older. Ask RSC ,I cut 8 head of Friction ,Carnac an Heat Wave embryo Cale's last year that we were partner's on. Freddy PS- Put these calve's that are just cut out where they have plenty room to exercise an prefer on grass to keep it clean.