Abstract
The concept of irreversible investment is applied to highly contagious animal disease control when uncertainty about the spread of the disease is resolved over time. In comparison with the strategy of destroying infected herds, the vaccination programme causes additional losses that cannot be recovered. These sunk costs are thus irreversible. Therefore, the gain from waiting for new information, namely the quasi-option value, should induce animal health authorities to delay the decision to vaccinate if the probability of a widespread epidemic is not too high. A numerical example is developed for foot and mouth disease (FMD) in Brittany. Keywords:contagious animal disease, irreversible control strategy, foot and mouth disease, gain from waiting