This is probably going to go against what most horse riders consider to be the general rule when it comes to saddle pads. I do not condone pressed wool pads but there are far better materials that can be used next to the skin of the horse. I always like to put the wool blanket next to the horse and if needed the wool pad on top of the blanket.
Natural wool fibers and why.
What is Merino wool made of? Typical Merino fleece will contain fibers between 10-25 microns in diameter and 1/2 to 1" in length. Mohair fiber is approximately 25–45 microns in diameter and a little longer at 1" to 1 1/2" in length. In each type the hair is hollow which gives it great ability to dissipate heat and moisture. On top of that it has microbial properties which help aid in keeping a lot of fungus at bay.
Merino wool is a natural, renewable fiber—meaning one sheep can grow four to five pounds of wool per year. Plus, this fiber has evolved over the years to keep sheep comfortable in harsh environments. These happy animals hang out in temperatures that range from 5 degrees to 95 degrees—no problem. It’s a pretty amazing fiber.
What is Merino wool really good at? Helping keep the horses body at a stable temperature. When it’s cold outside, the natural crimps and bends in its fibers trap air, insulating. When it’s warm outside, it transports sweat quickly away from the back, helping to keep it cool and dry.
This benefit of wool gets a bit technical—so bear with us. Merino wool transports sweat and moisture away from skin as a vapor. Merino fibers are inherently porous. They’re composed of little plates that moisture vapor can get in between. Pressed wool pads are not as porous. They are not able to wick the sweat away as it’s already a liquid, and becomes trapped between the pad and horses body. This is in essence what happens with a pressed wool pad. Pressed wool pads are compressed under steam under enormous pressure 100,000 lbs plus. This heat and pressure collapses the hair follicles taking the hair fibers natural ability to remove heat and moisture. Merino and Mohair takes a step out of the process.
Is Merino and Mohair wool better at than traditional wool? Science shows that it has the best heat dissipating properties of most of the wool species. It’s super-fine and soft. A single Merino wool fiber is ⅓ the diameter of a human hair. It’s so fine, actually, that when it brushes up against skin, it bends out of the way. It can’t be prickly like other wool fibers because it can’t stand up to the weight of itself. So it’s soft. Really soft. That helps in keeping the blanket from chafing the skin. Remember heat is the enemy here.
How to Use Your Saddle Blanket and Pad
I use the Merino or Mohair blanket next to the skin and then if i need extra padding to build up for a smaller horse's profile I use as thin a pad as possible on top of the blanket. Typical pad sizes come in 1/2", 5/8", 3/4" and 1" wool pressed pads.