1) Traditionally, animals such as cows and sheep have been marked by their owners so that the farm to which they belong might be identified.
The practice is on record from the sixteenth century but it probably has a much earlier origin. In some cases, the horns were burned but more usually the marks could be distinctive cuts to the ears, or colours applied to the hide or wool. It is in these circumstances that prop has been recorded in the Dales: 1685 one Weather which had A prope on the nar shoulder & A prope on the far hugh bone, Conistone
1688 a prop of the farr hook-bone, Litton
1698 sheep marked with a prop of the nar side, Ingleton
1729 a prop of the far hook-bone, Greenfield. The mark was probably made with ruddle, as in an example from west Yorkshire noted by Wright in an advertisement for a lost sheep. However, the origin of the word is obscure, although a connection with ‘property’ may be possible.