Abstract :
The long term studies with dairy goats on the effects of deficient semisynthetic feeding
rations in one of 16 elements as reported in the annual proceedings of the Workshops on
Minerals and Trace Elements and the International Trace Element Symposia by the University
of Jena, Germany, since 1975 until today were reviewed. The development of the
complex semisynthetic ration system was particularly important as it enabled to produce
significant deficiencies of single elements in long term replicated studies and their interactions
with other elements. The studies focused mainly on determining deficiency levels for
each of the 16 elements, identifying deficiency symptoms and reasons for them, and establishing
evidence for essentiality of the elements according to 7 criteria. Large amounts of
analytical data were accumulated showing the changes in organ and tissue contents of
the elements under study at normal and deficient levels, and their relation to impaired
reproductive efficiency, growth, milk production, health, and mortality of goats and their
kids. Histological sections of organs also showed their ultrastructural changes due to the
elemental deficiencies. Most element deficiencies caused reproductive failures, reduced
growth and milk production, but high mortality, while the control goats thrived on their
semisynthetic but sufficient ration, attesting to its completely correct biological value. The
identification of the reliable “indicator” organs and tissues for the diagnosis and detection
of deficiency status of the specific elements in goats is of particular value to veterinary
medicine and animal nutrition.
