It might depend on how many mg per ml. I've seen several strengths used by vets. In any case, if you're taking your cat or small dog's bupe sublingually, and you have little to no tolerance, about two to three of your pet's doses would most likely be your safe starting point, IF you're taking the liquid sublingually. (You're aiming for 200 MICROgrams, which is a starting dose when this is used in humans. Please note that's MICROgrams, NOT milligrams. First determine how many mg are in the dose by multiplying the drug strength (mg/mL) times the amount of liquid in the dose. Then convert those mg to micrograms using a conversion calculator.) If your route of administration is intranasal or intrarectal, keep in mind that the bioavailability goes from about 30% for sublingually to 50-60% for these two methods. Shooting the kind of bupe you've got really really sucks, bc of the nature of the drug, you don't get hit hard with it, and then you just get weird uncomfortable effects. I strongly recommend snorting the stuff. Also, you'll know within an hour how strong it is affecting you, so take some, wait an hour, do a little more if needed. With no tolerance just snort one dose to start.
