The magic behind ivermectin is that when you "worm" yourself and kill of a bunch of bad microbes it gives your body the nutrition back that they have been consuming and that allows all sorts of good things to happen.

Animals usually develops a nice shiner coat too.
Energy levels rise, hormone production happens easier and the ability of the bodies immune system gets to fight infections and virii instead of wasting it's energy fighting the microbes and junk the ivermectin kills off.

One reason that a simple wormer medication can help you right the Rona.