How much apple cider vinegar to mix in daily feed for horse fly control?

To use Apple cider vinegar for fly control in horses, mix 1 to 2 ounces of Apple cider vinegar per day into their feed. This amount can help deter flies due to its strong odor, which many insects find unpleasant. It's important to monitor your horse for any sensitivities and adjust the dosage if necessary. Always consult with a veterinarian before making significant changes to your horse's diet.