If we have to saw horns off a bought cow, we usually use the dehorning wire, as it cauterizes as you saw.
However, years back when I worked at the auction mart, we dehorned with the big cutters. To slow/stop bleeding besides cauterizing with a hot iron, you can also try this ( have tried the stop bleed powder and not overly impressed):
(Going on the premise that you already have the animal in a headgate, and sure does make it easier if you can throw a rope over the animals head and snub it to keep the animal as immobile as possible.)
1.Take a length of baling twine (you'll figure out how long to cut it as you keep reading).
2.Make a "figure-eight" of the twine by going around the base of each horn and crossing in the middle of the skull.
3. Pull as tight as you can. If you're lucky enough to have help, here's where you can use it, as you can now tie the twine as tight as possible, and it can be tricky to maintain tension while tying off.
4. Wash the blood from the spraying arterial bleeding out of your ears, off your face, and change out of your coveralls before someone mistakes you for an axe-murderer.
5. Cut the twines in the next day or two.
Take care.