my latest bottle of lactulose comes with a measuring cap on top. Pour some sticky muck into the cap, then syringe it up. Then wash the cap straight away as this stuff sticks! 1ml - 1.5mls is actually very little when you see it. I would start with a lowish dose (say 1mls), then if it doesn't work, try 1.5mls and if that works a bit too well, adjust from there. Ideally get a clearly marked 2.5ml or 2ml syringe from the vet (hopefully would give you one) or you can buy very cheaply at a chemist. Good luck.