Vacuum your rug regularly, before your cowhide rug becomes heavily soiled. Use your vacuum's floor attachment to brush the hairs in the direction of the grain, while lightly sucking out dust and dirt particles. Do this on a weekly basis so that the gritty pieces don't begin to cut the hairs of the hide. If possible, flip the rug over and shake out embedded particles.
Don't soak the rug, but you can lightly steam clean it without any adverse effects. The hairs in the hide are made of organic material. Hide material is meant to shed moisture. If it does get too damp, take it outside and flip it back side up to dry in the sun.
Remove spots with a non-alkaline soap. Leather soaps work for stains on a smooth hide, but baby shampoo or mild dish detergent worked into foam is better for hides with hair. Apply the foam to a sponge and lightly wipe the hide in the direction of the grain until the spot is dissolved. Rinse with a damp sponge to remove shampoo residue.
Use Scotch Guard or a similar fabric protector before your rug becomes stained, or after it is clean. It will help the hairs to repel stains.