Productivity loss and cost of bovine tuberculosis for the dairy livestock sector in Ethiopia

Bovine tuberculosis (BTB) is endemic in Ethiopia. Although upgraded dairy cattle account for only 1% of the total cattle population, they are the backbone of the marketed milk production in the country. Supported by research data outputs from three years, we report in this paper an estimate of the productivity loss and cost of BTB to the Ethiopian dairy sector in two dairy settings, the urban production system in Central Ethiopia (model 1) and the national upgraded dairy production (model 2). Primary data sources were used (e.g. market survey; three-year longitudinal productivity survey; abattoir survey) as well as secondary data sources. A matrix population model, composed of a population vector representing the herd composition that is repeatedly multiplied with a projection matrix, was developed to simulate the livestock dairy population. The initial herd structure was simulated over 30 years to obtain an equilibrium herd-structure representing an Eigenvector of the projection matrix. We performed an incremental cost of disease analysis by comparing livestock production with and without BTB during a period of 10 years. We assumed a BTB prevalence of 40%. In year ten, the Net present value (NPV) of livestock production in terms of milk, meat and hides was estimated at 154.5 million USD for model 1 and 1.7 billion USD for model 2. Loss of NPV over 10 years was estimated at 12 million USD for model 1 and 131.7 million USD for model 2, representing roughly 7.3% loss in NPV or 219 USD per animal. This is a benchmark against which a national TB control program could be developed in the future to calculate its benefit/cost ratio.