It is just SO hard to draw up a dose with any accuracy for dogs when the product is designed for horses! Let me show you...
Here is the volume of HORSE heartworm medication that you would need to get the same amount of ivermectin as in the Nuheart product for dogs:
Dogs up to 24lbs - 0.0036mL of horse heartworm medication
Dogs 24 - 50lbs - 0.007mL of horse heartworm medication
Dogs 51 - 0.015mL of horse heartworm medication
Now, the smallest syringe I have is an insulin syringe. One gradation on this is 0.01mL. So, you could draw up the dose for the largest dog using this... but not for the Min Pin! If you gave her just half of that it would still be more than 10 times her dose.
Now, I *have* heard of people using the Ivermectin sheep drench (Ivomec Drench for Sheep) as you can see here:
This product is designed for animals more similar in size to a dog than a horse is, so it is not as concentrated, so easier to draw up a more accurate dose for a dog. I cannot recommend doing this, as this is NOT what it is labelled for. But I can tell you the volume of the sheep drench that you would need to give the same amount of Ivermectin as in the NuHeart products. Ivermectin can be given orally.
Dogs up to 24lbs - 0.085 mL of SHEEP heartworm medication
Dogs 24 - 50lbs - 0.17mL of SHEEP heartworm medication
Dogs 51 - 0.34mL of SHEEP heartworm medication
If you were using an insulin syringe to draw this up, the little dog would get the equivalent of "8.5 units" of insulin. A pharmacist could show you where this mark would be on the syringe. The medium dogs would get the equivalent of 17 units, and the large dogs the equivalent of 34units.
Again, I really cannot recommend doing this! However, if you insist on doing it, the Sheep drench is FAR safer than the horse dewormer because it is not as concentrated so there is not so much chance of overdosing them.
I hope this helps! Best wishes! Fiona