Why are some horses more affected by midges?

[AWinter]

Two of my horses are being driven mad the last few days despite being in full sweet itch style rugs, lots of stomping, face rubbing and tail swishing going on when I check the cameras at night. Yet the other two horses who are unrugged seem unbothered apart from the odd tail swish.

Is it a horse colour thing? A thicker coat thing?

I’m trying yet another fly spray/balm tomorrow as I just can’t seem to get them comfortable.

 

[GoldenWillow]

My cob is bothered by midges but although they are around the shetland they don't really seem to land on him to the same extent. I appear to be a midge magnet and am plagued by them, always getting bitten, whereas they mainly leave OH alone.

 

[Barton Bounty]

Orbi was plagued this morning by them, just put him in, no point in trying to rub on trees etc

 

[HopOnTrot]

Same as people, I used to react really badly to them but now I’m on drugs that suppress my immune system I don’t find them that bothersome. It’s also all but fixed my hayfever. The advantages of rheumatoid arthritis

 

[PurBee]

Midges detect victims by heat signature, and when close-by use scent too.
It’s likely your rugged ones are showing a higher heat signature than unrugged, hence them attracting more midges. Where there’s heat theres blood, so midges cant resist a very toasty heat signal from a massive mammal. They likely are getting in underneath the rug as they’ll be automatically attracted to heat.
Theyve climbed through tiny holes in my socks to get my ankles! Any gaps in clothing they easily detect, so for a horse rug, there’s plenty of loose seams for them to climb into the hottest skin.

Out of mine, i find the darker one gets plagued by them more than lighter coloured one - the darker one is likely hotter than the lighter coloured one.

Unrugged, mine go in the dark cool corner of the barn when theyre really swarming and are left alone. Its dry in there and midges hate dry conditions.
The damper areas of my fields with loads of trees and bushes, and the one with a stream around it are the worst for midges, clouds of them everywhere when conditions are dull cloudy, still air with no wind and damp, just after rain is the worst.
I make sure to give them drier exposed breezy areas to go to get away from midges.

Most midges hate sunlight and dry conditions, so its best horses go out in the sun when midges are about and not stand in the shade of trees/bushes - which is where midges hatch from and there are usually clouds of them in natural damp shady areas.

For horse flies, its the other way around. They prefer full sun conditions and dont like the shade - my horses have worked that out at least and hide under trees, or in the barn when theyre really ferocious on the sunniest of days.

Oily sticky fly sprays work better and last longer than thin water based ones that soon evaporate off. Midges get stuck to cream and oils and die.
Spray the hottest and most shaded areas of the horse’s body that midges are automatically attracted to - sheath/udder, inner legs, under belly, topline, armpits, under chin, head/ears, around eyes gently with cream. Eyes are hot visually to midges hence why they’ll be around their eyes a lot.
If you rug daily, you could try a thick fly-killer cream thats spread as a line all around the body where the seam sits against their skin. Midges will land there to climb underneath and be caught by a line of sticky cream.

Im undecided scientifically, but i suspect any fly spray with vinegar might attract biting insects once theyre near the horse. Maybe vinegar mimics a pheromone they are naturally attracted to? - maybe its a similar signature to animal sweat? - i dont know …..but i tested a homemade vinegar based recipe, and freshly sprayed the insects landing didnt like the mixture, because its so potent maybe, but after the spray had settled on the fur and dried a bit, the vinegar was the over-riding scent and more were attracted to the sprayed horse rather than unsprayed horse.
These were horse flies i was testing at the time.

Midge machines work via heat and using a scent - so those 2 aspects attract most biting insects. Hence why some essential oils work well as theyre the opposite of the scent they like. Keeping a horse cool would be almost impossible as theyre huge hot blobs in a field, from the visual viewpoint of a midge. So we can use sprays, and try to give drier, breezier areas for horses when midges are at their worst.
Turning out into a very sheltered damp lowland fields will have midges plaguing the entire time. Id cover a horse head to toe in sprays and spend a fortune on sprays if i had no other turnout areas. Even at night turnout such areas will be plagued with midges if its a mild 10+ degree evening.
With really bad damp wet midgey summers, its oftentimes best to switch to night grazing and in during the day. Damp sunrise and sunset hours are when they peak swarm.
We’re in midge heaven, amidst thousands of acres of damp sheltered forestry, and the dry bedded barn, breezy areas principles have worked for us, aswell as changing turnout times, and using sprays.
Using shavings is better than straw for midges in their stable, as shavings are much drier, and they’d get dried-out and die when the midges inevitably land there on the ground to rest. Theyre used to going to the damp mud ground, or onto damp foliage, but the ground in a stable if kept very dry, will dry them out and kill them.
Have a fan in the stable mounted high pointing down will also dry them out and kill them. These are useful at peak swarming times.

 

[AWinter]

It’s interesting, I’m now having success covering their sheaths in ear balm of all things, then spray on top. Weirdly these two horses were being plagued before I rugged them, I couldn’t leave them without the sweet itch rugs they were demented.

One of them does seek out a particular corner of the barn and seems to find some peace there. The one that seems completely unbothered is a very fat, hairy white cob, barely a tail swish to be seen.