Join Date: Oct 2008
Location: Adelaide, South Australia
Yeah if you're buying different hay every month (i'm in the same boat, my fodder store uses a few different suppliers), getting tests is just a waste of money.
Aim for getting a GENERAL idea of what the land in your area is like (ie some places might be entirely deficient in iodine, or copper, or god knows what) and adjust your horse's diet accordingly.
It never hurts to throw the basics in anyway, my horse gets garlic (full of sulphur, and is antibacterial, antifungal, anti parasitical), rosehips (source of vitamin C, good for lungs and hooves), seaweed (helps absorb all other vits/minerals), brewers yeast (full of B group vitamins) and apple/cider/vinegar oil. I keep forgetting to add it, but I'm supposed to use copper sulphate (teaspoon a day as well) as Australia has barely any copper.
There are quite a few fantastic books on this subject- make sure you cross refernce though, and don't take the first book you see at face value!