Repel kills or repels:
Midges
Ticks
Flies
Mosquitos
 
Repel affects an insects neurological system which stops them from latching on and biting your horse which can transfer insect born deceases such as African Horse Sickness, West Nile Virus or Biliary.
 
Midges are most likely to bite the soft part of the skin because they have mandibles that saw through the horses skin and their short probiscis sucks the blood which is used to mature their eggs.
 
The rule of thumb is 1.5litre per horse per month.
Can also be used around mangers, doors and buckets.
Your horses will love you for this
 
Learn how to apply here.