Dont be too shocked about horses' weights: i recently put my fine-boned 15.2h Arab-esque Saddlebred on the local clinic's equine scale:
I almost fainted dead away. My gelding is *not* fat by any means.
Now Im terrified to put my IR Draft-cross on the scale...but theyre both going this week; part of my racketing down plan to evaluate each objectively.
When i relied on a weight tape i would clip a bit of hair on top of withers & belly so i always (or tried to) align the tape in the same spots. Made me feel better, FWIW.
All I can say abt the ACTH results is my gelding was *horrible* during the blood draw--jumping around, trying to lay down, even managed to bite me despite a chain shank & experienced holder. It was during an insulin spike so at least I anticipated the inevitable tantrum. Anyways, his ACTH was only 7.1 (ish) at Cornell (dont have exact number in front of me). However, that isnt to say that a PPID horse might not raise endogenous cortisol differently than a non-PPID...idk. However, if "stress at draw" was ever going to influence a healthy horse ACTH--it def woulda been that draw on that horse!! Yikes!
Kerry in NY