In the hot summer months when my horses are sweating alot which electrolyte supplement would you recommend feeding them? There are so many on the market and so many articles about which ones to feed and which ones to avoid. Thank you. – via AAEP Ask the Vet

I agree, there are a lot of choices out there when it comes to electrolytes! And since replacing the vital nutrients lost in sweat as well as encouraging horses to drink and rehydrate themselves are both critical to your horses’ health, let’s see if we can help you sort things out.

Some things to consider when choosing an electrolyte are palatability (ie tastiness), the presence of extra or unnecessary ingredients (like sugar), and how closely the supplement mimics the minerals horses lose in their sweat. The ideal equine electrolyte therefore would be one that horses eat readily, that contains little or no added sugar, and that is formulated to replace what is actually lost from the horse due to sweating. Numerous studies in this area have shown that the major ions found in horse sweat are chloride (Cl), sodium (Na), and potassium (K), in that order, with a little bit of calcium (Ca), so look for a supplement with primarily these macrominerals. Here’s a fact sheet with more detail about sweating in horses and electrolyte supplementation to replenish losses.