Golden Hoof is a zinc sulphate powder which makes up a less environmentally-damaging footbath for footrotty and scaldy-footed sheep (and sounds like goats too) than formalin does.
Formalin works, is simple to use but is noxious to the operator and can be to the sheep, and is very environmentally damaging. It also causes damage to the hoof if used repeatedly over the long-term, so is not ideal for a routine treatement for breeding sheep, and should not be used by asthmatics or others with breathing issues.
Golden Hoof works if you can use it according to the instructions and is considerably less noxious to the operator but is less simple to use than formalin. It is less environmentally damaging than formalin on two counts. Firstly, formalin can only be used once, really, as it becomes less effective against bacteria (though sadly just as quick and horrific at killing amphibians and fish) immediately organic material gets into it - and unless you put nappies on your sheep while they run through it, and wash their feet thoroughly before they enter the bath, it will be contaminated after one use! Golden Hoof, however, can be reused - the vet reckons up to 5 times - as it is not affected by the dung and urine that get into it. Secondly, the chemicals in Golden Hoof are less noxious to the environment than formaldehyde - though I couldn't quantify that for you.
HTH