Vitamin A absolutely WILL fix existing rain rot. It is the only way I have treated incoming cases for about 40 years now. I have had it clear up horses that were so bad you could not touch their sore backs and rumps. They were nearly one big bloody scab. It started clearing up within days with absolutely no topicals.
You just have to give them a couple of big doses of injectable Vitamin A made for cattle. GIVE IT ORALLY - not inject it. Start them on a good mineral or feed with plenty of Vitamin A in it and it will be gone in no time without Listerine, MTG or Betadine.
There you go again.
Earlier you said rain rot was caused by a deficiency in vitamin A and then asserted it could be treated by feeding supplemental vitamin A.
I was most concerned to see what I consider to be misinformation erring on the side of "dangerous and incorrect advice"
But I gave you the benefit of the doubt and asked you to
cite the evidence for your statement re root cause and also that it's clinically effective in treatment.
Because you made mention about vitamin A deficiency and immuno compromise I aslo asked you how you were checking the immune status and vitamin A levels for your horse
You never answered any of the questions posed.
However I feel somewhat obligated to ensure that there's a strong awareness and specifically a correction and caution issued with regard to your "advice" to slam in injections of vitamin A.
Horse owners need to know that giving vitamin A when it's not required is risky and specifically with risks of toxidity.
Vitamins are divided into 2 categories: fat soluble and water soluble. Vitamin A (E, D & K) are all in the former category. Fat soluble vitamins with the exception of vitamin E are more likely to be stored in large amounts in the body and are more likely to be toxic when fed in excessive amounts.
The liver can store a 3-6 month supply of vitamin A and it's quite unusual for a horse to be deficient in vitamin A because of this ability.
If green forage, yellow/orange grains and/or carrots are fed at all then the horse will be getting it's recommended daily requirement which for a working horse is 1400 IU/kg feed.
Signs of deficiency are night blindness, corneal cloudiness, impaired growth, reproductive problems, poor conception rate, abortion, testicular degeneration, ataxia, convulsions.
Toxicity or overdose of vitamin A shows up as bone fragility, peeling or scabby skin
, ataxia and a low red blood cell count.
And you can't compare a cow's nutritional requirements for vitamin A with a horse's. It is indeed quite common to inject cattle with vitamin A in the winter when they're totally off all green forage and eating only straw or cattle cake. But not at all appropriate for horses. Indeed IMO most dangerous advice!