Synchronous diaphragmatic flutter, thumps for short, is a metabolic disorder in horses. Typified by rhythmic twitching of the muscles near a horse’s flanks, thumps is a warning that his internal calcium reserves are running low.
Laurie Bonner and Melinda Freckleton, DVM, share how to address active thumps in horses when they occur and how to avoid future incidents in horses with a thump history.
Source: EQUUS Extra, Volume 67, page 12. Link. Administering electrolytes may help a horse with thumps replenish his stores, but do not overdose him in an attempt to speed his recovery. Always offer plenty of fresh water to any horse resting after exertion but especially after you’ve given him electrolytes.