So how much paste is that?
How much do you weigh?
That would mean a dose would be:
.2 mg/kg X 90.72 kg = 18.14 mg of ivermectin = 16%
.4 mg/kg X 90.72 kg = 36.3 mg of ivermectin = 32%
.6 mg/kg X 90.72 kg = 54.4 mg of ivermectin = 48%
If a tube/syringe has 6 grams and that equals 113 mg of ivermectin at the density you mentioned, the percentages above should do it well for your 200 pound pet.