| In order to study the economics of vaccination in grass carp, a mathematical model was constructed to analyse the costs and benefits of vaccination based on the principle of alternative cost. A cost-benefit study of vaccination in grass carp in north China was made by using this model. The result showed that the benefit-cost ratio of immunized ponds was 7：1, and the benefits added 14 500 Yuan/hm2 due to vaccination. Therefore, the benefits of vaccination in grass carp was good. The net benefits of vaccination increased with the disease challenge pressure and the relative percent survival (vaccine efficacy) increasing. Break-even point(BEP) analysis showed that,if the other conditions were unchanged, the BEP was on the point that the relative percent survival was 15.3% or the mortality of unvaccinated fish was 1.8%. The sensitivity analysis showed that vaccine efficacy had a more significance influence on the net benefits of vaccine than on the costs of vaccination, with the increasing of disease challenge pressure. This mathematical model can be used for costbenefit analysis of vaccination in grass carp, which can help the government, enterprises and farmers make the best decision of vaccination. |
