Biteback’s Danielle has noticed that her dun Connemara, Phoenix, seems to attract far more flies than her other horses — Moses, the coloured, and Gem, the grey. So, what’s going on? Why do some horses attract more flies than others?
(Phoenix - the 'fly magnet')
The truth lies in a mix of biology, behaviour, and even a little horse “perfume.” Let’s break it down.
Sweat Chemistry: The Fly’s Dinner Bell
Flies aren’t just annoying — they’re strategic. They seek out scents that tell them a host is nearby. Horses naturally sweat to cool down, and that sweat contains lactic acid, ammonia, and salts.
Some horses produce higher levels of certain compounds, especially lactic acid, which can be irresistible to flies. Think of it like one horse smelling faintly like a salad, and another smelling like a five-course buffet.
Body Heat and Movement
Flies use infrared cues (heat detection) and movement to find their target. A more active horse, or one with a slightly higher body temperature, can be a beacon to flies.
It’s like waving a neon “OPEN” sign in fly language.
Coat Colour and Light Reflection
Research suggests darker-coloured horses may attract more flies, particularly biting species like horseflies. Dark coats absorb more heat, which can make them easier for flies to detect and home in on.
Grey or light-coloured horses sometimes fare better, though it’s not a fool proof shield.
Skin and Hair Condition
Flies are also drawn to areas where the skin is damp, irritated, or has open wounds. Horses with skin conditions, sweet itch, or healing cuts might be more attractive to them simply because those spots offer easier access to feed.
Smell of Manure and Environment
Where the horse lives plays a big role. Horses standing in or near manure piles, wet areas, or stagnant water will generally have more flies around them. And yes, some horses are just messier — rolling in mud or lying down in damp bedding can make them smell more appealing to a fly’s finely tuned nose.
Individual Variation (The “Mosquito Effect”)
Just like how some humans swear mosquitoes love them while ignoring their friends, some horses simply emit a combination of odours and heat that’s more attractive to flies.
It’s an unfortunate gift — one that comes down to genetics and individual body chemistry.
What You Can Do About It?
While you can’t change your horse’s scent chemistry, you can make them less appealing to flies:
- Fly Fringes and Zebra Sheets
- Regular grooming and removal of sweat - use Sweatbuster or Sweet Relief Shampoo
- Wound management - Sweet Relief Silver cream to support the skin's natural healing.
- Manure management
- Fans in stables
- Repellents
Bottom line:
Some horses are simply born fly magnets thanks to their unique combination of sweat chemistry, body heat, and behaviour. While we can’t rewrite their DNA, we can make them less of a target — and maybe even reclaim a few peaceful summer afternoons without the constant tail swishing.