(i) OK. You might want to consider saying "his goats" rather than "the goats" (but "the goats" is not wrong).
(ii) This is wrong. I think you should be able to see why.
Vincent Teo His work was watching over the goats from dawn to dusk.
Peaceblinkfriend Vincent Teo His work was watching over the goats from dawn to dusk. I hope you don't mind me using your sentence as an example, Vincent.I was just wondering whether 'His work was to watch..." sounds more natural?
Both seem OK to me.