Let's get a lil perspective here folks. A Red Bull has 80 milligrams of caffeine, Monster is 240 milligrams and a cup of coffee can run anywhere from 75-300 milligrams per cup depending on the style of coffee. As a health professional, I advise my patients to keep caffeine intake under 400 milligrams per day otherwise you can cause yourself health problems. Now that's a person...I don't really think 80mg of caffeine would really affect a horse weighing 1000lbs.
We grow too soon old, and too late smart.