The correct option is C Diagnose and cure once the disease symptoms are noticed
The cattle in the farm are affected by many factors like water, fodder and climatic changes. This in turn affects the products from them. For example, milk production is affected if the climatic conditions are harsh. According to the given scenario, if all the animals were culled in a farm and you are beginning with a new batch of cattle, you should make sure that you selectively breed disease resistant cattle and also follow prevention methods in susceptible herds rather than waiting for the disease symptoms to occur, which might lead to culling again.