of vitamin b12. other animals ruminants, such as cattle and sheep, absorb b12 synthesized by their gut bacteria. sufficient amounts of cobalt and copper need to be consumed for this b12 synthesis to occur. in the early 20th century, during the development for farming of the north island volcanic plateau of new zealand, cattle had what was termed "bush sickness". it was discovered in 1934 that the volcanic soils lacked the cobalt salts essential for synthesis of vitamin b12 by their gut bacteria. the "coast disease" of sheep in the coastal sand dunes of south australia in the 1930s was found to originate in nutritional deficiencies of the trace elements, cobalt and copper. the cobalt deficiency was overcome by the development of "cobalt bullets", dense pellets of cobalt oxide mixed with clay given orally, which then was retained in the animal's rumen.