Hi, I haven't been on this forum for quite a few years, after my old desktop passed away and I forgot I was a member here, until I just tried to join
Regarding sweet itch. I am in the U.S. but we have horses who can have allergic reactions to the midge fly bites every bit as bad as horses in the UK. I had an Arab who was horribly allergic to midge fly bites and every spring it was an uphill battle to keep his belly line free from bites.
I did find a cure that lasted him several years until he passed at age 29, but first:
1. I kept his belly line washed twice daily and applied a combination of diaper rash cream that says "40% zinc oxide" on the label and hemherroid (sp?) ointment. The flies can't bite thru the diaper rash cream plus it stays on all day. The hemherroid ointment helps reduce swelling/itching.
2. Midge flies also lay microfilia under the skin, known as Onchocerca worms, aka neck threadworms. They aren't worms in the true sense but they can migrate into the eyes on rare occasion. If your horse has unexplainable sores on its face and neck, those are the neck threadworms.
They will not show up in a fecal exam as they are under the skin.
My Arab also had those sores. The first thing I did was to double dose him with pure Ivermectin. That means two full tubes of Ivermectin down the hatch at the same time. He was only 13.3H, so I was a nervous wreck; it took me two years to work up the nerve and I kicked myself afterward for waiting for so long.
Some horses need dosed again in a month but he didn't.
After he was done recovering from the NTW's rebelling under his skin at being "murdered", I ORALLY gave him 10CC's of injectable cow vitamin AD. I only gave it to him one time, at two week intervals, for only one month IN HIS FEED PAN.
My horses are on our farm. We don't have cattle but we live in a big cattle producing county so the Vitamin AD is readily available. The Valley Vet catalogue has it and no prescription is needed.
You just have to know you need a needle to draw it out of the bottle, then squirt the 10CC's into the feed pan - never inject it into the horse.
My Arab stayed "clean" of sweet itch for the next three years, until his end, plus his coat even became much softer and a richer color,
I know it all sounds "snakebite medicine-ish" but it does work. There is a gigantic thread on this subject on another forum but I don't think I'm allowed to link to the competition - it's where I got all my information to work up the nerve to dose my precious Arab
I hope this is helpful