A yoke is the piece of harness equipment that connects two draft animals side-by-side; it’s sometimes more fully blazoned an “ox yoke”. It’s a period charge, found in two somewhat different forms: a Continental form, seen in the arms of von Mengersreuth, c.1370 [Gelre 44v; also Siebmacher 89]; and a British form, which was the badge of the Earls of Errol from at least the mid-16th Century [HB 99; also the Dunvegan Armorial, 1582, f.31].
The yoke is fesswise by default. The British form, when “proper”, is colored brown, as with all wooden charges.
The Shire of Belle Rive bears as a badge: An ox yoke, beamed vert, bowed argent.
Henricus Guotman bears: Per fess wavy vert and purpure, in chief an ox yoke Or.