Will legal trade of horns save or eradicate rhino population?

Wobbling left, then right, the two-tonne animal stumbles and starts to fall. Twelve pairs of hands are there to ease it towards the dusty orange earth.
A man wearing a blue work suit quickly straps an eye mask over the now sedated beast; another slips in a pair of massive earplugs. A few measurements are taken, and then the reciprocating saw comes out.