There is no specific duration of Derfen. Basically, it will depend on what your horse needs but above all its skin. The thicker it is, the fewer applications the horse will need.

In order to make sure Derfen will be efficient, it must be applied as often as your horse needs it. Any sign of itching must be retaliated without delay by applying Derfen on the affected areas.

Results are outstanding no matter what type of horse it may be. The environment of the horse or even its food will not impact on the efficiency of Derfen. If you do not notice any result, you should investigate its skin problems one step further. Is it really a SSRD? A great deal of dermatitis look like SSRD but there are not real ones: your horse will need different treatments.