Cattle in certain paddocks may eat clay or tree-bark in those paddocks but not in adjoining paddocks. Grass in those areas may be grazed to the ground. Some outbreaks have no known cause and may not be solved by laboratory tests on blood or feed. The problem is more aesthetic than economic, as general herd health and productivity is usually normal. The causes are largely unknown .
Investigation usually is futile .
Otherwise, there appear to be few etiological factors in common. However, salt or high quality mineral mixes, even at high levels, often fail to control the problem.