Pulled manes are usually seen in dressage horses, jumpers, hunters and some western horses. Of course the winter season may put a halt to full scale baths for awhile but you can still give your horse a sponge bath or a hot towel bath and wash their manes and tails on milder days. Most importantly you need to keep your horse's fetlocks and pasterns free of dirt and debris as much as possible. If not you may find you have a fungal infection on your hands. White socks particularly need extra attention.
White hair is prone to a type of infection called scratches.
Scratches send shivers of fear throughout the most stoic of horsemen. You'll need to call your vet if you see signs of scabbing-the hallmark of scratches. In the wintertime you'll want to wash or rinse your horse's legs each week and inspect them for cuts and infections. Protect your investment by cleaning your tack each week. In fact, get into the habit of rinsing your bit and wiping your bridle and saddle after each ride.