Been up since 5am doing horse stuff so this may not all make sense!!!!
Yes a sweat neck cover will help reduce crest - one good way to test if the crest is just breed related is if its 'floppy' its generally OK but if its rigid its a warning sign
The 'Dick' Vet School (Edinburgh UK) has been doing a lot of research in IRS comparing horses and humans as its similar to diet controlled diabetes. There are a lot of indications that all diet related cases of laminitis are rooted in insulin resistance - hormone inbalances in hormones that are components of the blood stream.
I think it was Loosie who pointed out that breeds like drafts are prone to it - a genetic pre-disposition that UK native breeds, Morgans, TW's & several other breeds also have. The draft breeds were bred to work hard all day, on farms or hauling heavy carts, they would probably have had a feed when they had a break during the day and were often stabled at night for convenience just being turned out on rest days. We buy these horses and keep them on good grass, throw in extra feed and maybe work them a from maybe a couple of hours a day to just few days a week and it all goes wrong
When IRS sets in its as if the metabolism has 'crashed' from having to deal with too much sugar and the whole process of insulin production goes wrong as the body produces too much insulin that for some reason isn't effective. Blood sugar levels rocket and the glucose needed to maintain healthy celss and normal function doesn't get processed properly
I read an article about one IRS pony that was monitored as it was put on a regime of diet and exercise. Over a 7 month period his crested neck went from hard to floppy and his glucose levels improved & his laminitis had recovered enough for him to go back to normal work
Feeding a supplement of Magnesium and Chromium (like Quiessence) seems to give good results along with a strict diet
I'm going to try to put a link here that I found that has some good pics of what warning signs to look for http://www.safergrass.org/pdf/EMSgallery.pdf