Pow-Wows, or Long Lost Friend, by John George Hoffman, [1820], at sacred-texts.com
A VERY GOOD MEANS TO INCREASE THE GROWTH OF WOOL OR SHEEP, AND TO PREVENT DISEASE AMONG THEM.
William. Ellis, in his excellent work on the manner of raising sheep, relates the following: a tenant who had a flock of sheep that produced an unusual quantity of wool. He informed me that he was in the habit of washing his sheep with buttermilk just after shearing them, which was the cause of the unusual growth of wool; because it in a known fact that butter does not only improve the growth of sheep's wool, but also of the hair of other animals. Those who have no buttermilk may substitute common milk with salt and water, which will answer nearly as well to wash the sheep just sheared. And I guarantee that by rightly applying this means, you will not only have a great increase of wool, but the sheep-lice and their entire brood will be destroyed. It also cures an manner of scab and itch, and prevents them from taking cold.