If the tail shield includes a defecation tray, docking the tail may be preferred. With the gutter grate at the rear edge of the cow platform and no defecation tray on the tail shield, periodic tail switch trimming is all that is required. Dairymen and milkers with no experience in a parallel parlor are apprehensive of milking between the hind legs and consider this a disadvantage. Milkers experienced in milking between the hind legs say this is not a problem, and the safety gain is a major advantage. Defecation Study Milking from the side of a cow is part of cultural inheritance.
Most people react adversely when they first see milking between the hind legs.
Europeans do not use defecation trays or manure grates. They feel the 15-degree tail shield, and ready to access water hoses in the pit to wash away manure wastes, is adequate. U.S. dairy and sanitation practices tend to reinforce the cultural bias that calls for more protection. Early on, California regulators decreed that a manure tray must be added to the tail shield. In the absence of research data, this move sparked a small controversy.