You can get products which repel mud from your horse's legs and can get products such as baby oil which has been known to remove mud much more quickly. Despite these, I've never personally used them and my mare has never had mud fever, despite her coming in absolutely caked in mud.
If you're bringing your horse in and he has muddy legs, it's best to leave the mud to dry and brush it off the next morning. Washing off his muddy legs may actually promote mud fever since water softens the skin, meaning mud, sand or other soils can rub against, irritate and damage the horse's soft skin.
And always use white healer
Always try and keep ur paddocks dry as posible