thurl

Noun

 * 1)  Either of the rear hip joints where the hip connects to the upper leg in certain animals, particularly cattle; often used as a reference point for measurement.
 * 2) * 1918, G. C. Humphrey, The Rural Efficiency Guide, Volume 4: Stock Book, page 22,
 * Deficiencies which are common to the hind quarters of the cow, include shortness and narrowness of rump, a drooping rump, narrowness between the thurls and pin bones and thickly fleshed thighs.

Etymology 2
See.