Duvet and others make several variations of horse pastes. If the only active ingredient is ivermectin AND you titrate it to your body weight, or less than the next 50 lb increment, you should be fine. Of course, it's on you to make your choices and take your chances, but many of the problems have been either using a combination or different product, or using the entire tube which was designed for a 1250 lb horse.

Don't use a tube with a different main ingredient or two main ingredients!