I’m sure the intentions are good, but the risk/benefit ratio isn’t favorable. The likelihood of this outcome might be very low, but it isn’t zero. Anaphylaxis is a known side effect of injectable E/Se and giving meds off label in a cocktail may have risks that aren’t described in the literature. The benefits of this treatment are untested but probably dubious at best given that it’s not treating any specific deficiency but just being used for “recovery.”
Of course, vet med doesn’t have the luxury of all the research funding that human medicine has, so as a result it can be difficult to stick to pure evidence-based medicine. But if you’re starting with a completely healthy horse and using non-evidence-based treatments in pursuit of some vague benefit like “faster recovery,” they should at least be things that are not likely to cause actual harm. Most supplements fall into this category and probably don’t work and only create expensive pee, but at least don’t harm anything but the owner’s wallet. But giving a random cocktail of off-label drugs IV to a healthy horse, in a stabling? Hell no.
There is a way-too-prevalent mentality these days that proper care of horses means giving them “maintenance” in the form of injections, alternative therapies, chiropractic etc and most of these things aren’t based in any actual evidence at all. Horses aren’t cars. Horses’ bodies actually do quite well with proper nutrition, turnout, and proper training, and no injection or “bodywork” is a replacement for any of those things.
