What clinical sign is commonly observed in horses exposed to Haole koa?

The clinical sign commonly observed in horses exposed to Haole koa is mane and tail hair loss. Haole koa, or Leucaena leucocephala, is a plant that can cause photosensitization in horses, leading to skin lesions, particularly on areas with less pigmentation, such as the mane and tail. This can result in hair loss as the horse reacts to UV exposure while having a compromised skin barrier. It's important for horse owners and veterinarians to be aware of the risks associated with this plant and monitor affected animals for signs of irritation and hair loss, as this can be a visual indicator of a more significant underlying health issue due to exposure.