Waiting 60-90 days is best. Valbazen is the only white dewormer I know if that isn't safe. You can use Safeguard or Panacur. Problem is by itself at least here it's basically useless as there is a lot of resistance. However if using dual with Ivermectin I definitely wonder if it would work better. Safeguard used to be widely used on Thoroughbred horse farms years ago because it's safe but again... There is resistance so I don't know many who use it. Quest plus is a big one that is preferred from what I see.