Horse paste is only around 2% ivermectin. Hardly concentrated. Plus the dose ratio to give to a horse is substantially larger than the amount given to a rat.
I have a specific dose if anyone is really that interested, but eyeballing a rice grain size is fine and safe to give rats. I'm not saying your method is wrong either. Its not because I do the same time to time. But the horse paste isn't wrong either if done correctly
This is coming from someone who works in a medical research laboratory with lab rodents daily.
Sent from my DROID RAZR using Tapatalk 2