Hi I know some people use bute, others use aspirin. Here is my question- if you wanted to use aspirin for a horse- what is the dose (in human MG tablets) for a 1,000 pound horse. I ask because I read that it is about two to four 240 GRAIN BOLUSES. What the HECK is a grain bolus? More important, how does that translate to human aspirin. So say I had a giant container of 600 human aspirin and they are 325 MG each- how do I figure out how many of those to give the horse to be a proper does (how many 325 MG aspirins does it take to equal 240 or 480 grain boluses)? Can anyone help? thanks for any advice you can give. I don't use aspirin on a frequent basis- like Bute I only plan to use as needed but I just was working on my first aid kit and wanted to know how to dose.