Wound care is one of those many horse issues where there are as many opinions as there are horse owners. There are hundreds of agents (both commercial and homemade) available to paint, spray, smear, gob on, and cover wounds. You can use yellow ones, black ones, red ones, purple ones, and some people have tried very strange ones (used motor oil, for example). On wound care I am a minimalist; many available wound concoctions have actually been shown to delay wound healing or damage the tissue.
I often answer the question, "Is this OK to put such and such on a wound?" with "Would you put it on an open cut on your own arm?" The answer usually is a resounding "No!" Then why would you put it on your horse? More on these later.
Most wounds involve some degree of blood loss (a fact that can be extremely alarming to some people). Because of that, I think it would be useful to review some facts about blood and the horse.
Pop quiz: How much blood does a horse have? It varies some from breed to breed, but an average value is 80 mL (cc) per kilogram of body weight. So, the average 1,200-pound horse (545.5 kilograms) has about 43.6 liters or 11.4 gallons of blood.
So, if the average horse has about 11.4 gallons of blood, how much can be lost before the danger of shock becomes significant? The general rule of thumb is that an animal will start to show signs of blood loss shock when 10% of its blood volume has been lost. Based on the averages, the adult 1,200-pound horse can lose up to 1.4 gallons of blood before serious concern. Most bleeding from wounds appears to be a much larger volume o