If he/she said how much to use, then do so.
When I had to use it earlier this yr cause my mares foal got stuck and died in her, after removing the foal, my vet gave me the same stuff at 1mm (cc) every 1/2 hr. Then 2mm (cc) every 1/2 hr AFTER 3 hrs later if her plecenta still was'nt coming out.
Good luck!