Current weather and delay conditions for (GRU) Sao Paulo-Guarulhos International Airport Conditions
Another option is to mix small amounts of apple cider vinegar with the animal's drinking water; consuming this solution is known to change the blood pH of the horse, thus keeping horseflies away. Cider vinegar, coupled with essential oils, is also used in home sprays as the sharp odor may repeal horseflies.
Keep those Bugs off Naturally. Healthy Horse Hints for parasite control. Consider this; already diseased skin is more vulnerable to fly or mosquito parasites. Option 1: The herbs rosemary, yarrow and calendula are great to repel insects from wounds; try adding them to an aloe vera gel base to assist healing and deter insects.