Measuring the benefits of disease control: relationship between herd structure, productivity and health.

The influence of calving percentage and mortality levels on herd structures is studied. Standard herd structures with set levels of mortality are calculated for comparison with field data. Herd structures from field surveys in Zambia are studied in order to determine how these can be used to gain more information about herd input and output dynamics. Methods of calculating off-take and the problems relating to making such calculations are discussed.