This section is from the book "The Farmers Ready Reference Or Hand Book Of Diseases Of Horses And Cattle", by S. C. Orr. . Also available from Amazon: The Farmer's Ready Reference;.
Any and all animals are liable to be troubled with lice, and more especially those that are thin in flesh. Where only one or two are to be treated a mixture of one part oil of tar, two parts sulphur and four parts of lard well rubbed in about the head, mane and along the spine once a week for three weeks will effect a cure; but if a large number are to be treated the wash prescribed for mange will be cheaper and more readily applied.
Where chickens are allowed to roost or build nests about the stable, horses are apt to become infested with hen lice, and will rub and bite themselves wildly, while nothing can be seen except on the closest inspection. Any of the preparations for horse lice or mange will kill them, but the stable must also be cleansed or they will be as bad as ever in a day or two.
Ringworm is due to a vegetable parasite (Trichophyton tonsurans) which manifests its presence by small, round spots of bald scurfy skin, frequently about the head and face, but may come on any part of the body. It is contagious to man or beast and should not be neglected.
Treatment. - Wash off the scabs and apply tincture of iodine once a day for three days. Repeat at the end of a week if necessary.