Sorry I haven't been checking regularly.
Butchering does not prevent reanimation, but it does weaken it. Meat does not reanimate - only body parts. To completely stop an animal from reanimating, butchering it and then quickly tanning the hide into leather is sufficient. There is no way to stop a dwarf from reanimating short of a drawbridge or magma.
Ways are being discussed for future versions to have zombies eventually stop being reanimated, but in the current version, they cannot be destroyed in combat.
If you must engage a zombie in combat, blunt weapons are best. Melt down an anvil for iron if you have to, but for the love of Armok, don't use an axe. Especially not an adamantite one.
Blunt weapons have the highest raw damage values. They do consistent damage even against things with no vulnerable anatomy, which is what zombies are. Piercing weapons have the lowest damage, but the highest piercing value, which means they're the most likely to damage internal organs like hearts and brains. Against living creatures, that's great, but zombies don't care. Bladed weapons have medium damage, but can sever limbs. That would be great most of the time, even against undead, but not in this biome. Even a severed finger will just be another enemy, and another hauling job. Keeping the corpses intact means that it only takes a single hauler to bring them to the atom smasher.
My recommendation is to build another atom smasher, bait the zombie into it, and then atom smash it without a fight. Something like this:
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#XXXXXXXX#
+XXXXXXXX+
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X = Drawbridge (raises north). When pulled up, it will be a 1-wide hallway with doors at both ends.
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#========#
+........+
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Once a zombie gets inside, lock both doors and drop the bridge. No fight, no blood, no loss of civilian life.